1
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Zhang H, Shao YT, Chen X, Zhang B, Wang T, Meng F, Xu K, Meisenheimer P, Chen X, Huang X, Behera P, Husain S, Zhu T, Pan H, Jia Y, Settineri N, Giles-Donovan N, He Z, Scholl A, N'Diaye A, Shafer P, Raja A, Xu C, Martin LW, Crommie MF, Yao J, Qiu Z, Majumdar A, Bellaiche L, Muller DA, Birgeneau RJ, Ramesh R. Spin disorder control of topological spin texture. Nat Commun 2024; 15:3828. [PMID: 38714653 PMCID: PMC11076609 DOI: 10.1038/s41467-024-47715-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/10/2024] [Indexed: 05/10/2024] Open
Abstract
Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights the influence of random spin control of non-trivial topological spin textures.
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Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Yu-Tsun Shao
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Center for Neutron Science and Technology, School of Physics, Sun Yat-Sen University, Guangzhou, Guangdong, 510275, China.
| | - Binhua Zhang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China
- Shanghai Qi Zhi Institute, Shanghai, 200030, China
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Fanhao Meng
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kun Xu
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Sajid Husain
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Tiancong Zhu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yanli Jia
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Nick Settineri
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Zehao He
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Andreas Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alpha N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Changsong Xu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China.
- Shanghai Qi Zhi Institute, Shanghai, 200030, China.
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
- Department of Chemistry, Rice University, Houston, TX, 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA
| | - Michael F Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, 14853, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA.
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA.
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA.
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2
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Huang X, Chen X, Li Y, Mangeri J, Zhang H, Ramesh M, Taghinejad H, Meisenheimer P, Caretta L, Susarla S, Jain R, Klewe C, Wang T, Chen R, Hsu CH, Harris I, Husain S, Pan H, Yin J, Shafer P, Qiu Z, Rodrigues DR, Heinonen O, Vasudevan D, Íñiguez J, Schlom DG, Salahuddin S, Martin LW, Analytis JG, Ralph DC, Cheng R, Yao Z, Ramesh R. Manipulating chiral spin transport with ferroelectric polarization. Nat Mater 2024:10.1038/s41563-024-01854-8. [PMID: 38622325 DOI: 10.1038/s41563-024-01854-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 03/07/2024] [Indexed: 04/17/2024]
Abstract
A magnon is a collective excitation of the spin structure in a magnetic insulator and can transmit spin angular momentum with negligible dissipation. This quantum of a spin wave has always been manipulated through magnetic dipoles (that is, by breaking time-reversal symmetry). Here we report the experimental observation of chiral spin transport in multiferroic BiFeO3 and its control by reversing the ferroelectric polarization (that is, by breaking spatial inversion symmetry). The ferroelectrically controlled magnons show up to 18% modulation at room temperature. The spin torque that the magnons in BiFeO3 carry can be used to efficiently switch the magnetization of adjacent magnets, with a spin-torque efficiency comparable to the spin Hall effect in heavy metals. Utilizing such controllable magnon generation and transmission in BiFeO3, an all-oxide, energy-scalable logic is demonstrated composed of spin-orbit injection, detection and magnetoelectric control. Our observations open a new chapter of multiferroic magnons and pave another path towards low-dissipation nanoelectronics.
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Affiliation(s)
- Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Yuhang Li
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | - John Mangeri
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, Esch/Alzette, Luxembourg
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Maya Ramesh
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | | | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Rakshit Jain
- Department of Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Cheng-Hsiang Hsu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Isaac Harris
- Department of Physics, University of California, Berkeley, CA, USA
| | - Sajid Husain
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Jia Yin
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, USA
| | - Davi R Rodrigues
- Department of Electrical Engineering, Politecnico di Bari, Bari, Italy
| | - Olle Heinonen
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Dilip Vasudevan
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, Esch/Alzette, Luxembourg
- Department of Physics and Materials Science, University of Luxembourg, Belvaux, Luxembourg
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | - Sayeef Salahuddin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, CA, USA
- CIFAR Quantum Materials, CIFAR, Toronto, Ontario, Canada
| | - Daniel C Ralph
- Department of Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Zhi Yao
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
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3
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Meisenheimer P, Moore G, Zhou S, Zhang H, Huang X, Husain S, Chen X, Martin LW, Persson KA, Griffin S, Caretta L, Stevenson P, Ramesh R. Switching the spin cycloid in BiFeO 3 with an electric field. Nat Commun 2024; 15:2903. [PMID: 38575570 PMCID: PMC10995181 DOI: 10.1038/s41467-024-47232-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/26/2024] [Indexed: 04/06/2024] Open
Abstract
Bismuth ferrite (BiFeO3) is a multiferroic material that exhibits both ferroelectricity and canted antiferromagnetism at room temperature, making it a unique candidate in the development of electric-field controllable magnetic devices. The magnetic moments in BiFeO3 are arranged into a spin cycloid, resulting in unique magnetic properties which are tied to the ferroelectric order. Previous understanding of this coupling has relied on average, mesoscale measurements. Using nitrogen vacancy-based diamond magnetometry, we observe the magnetic spin cycloid structure of BiFeO3 in real space. This structure is magnetoelectrically coupled through symmetry to the ferroelectric polarization and this relationship is maintained through electric field switching. Through a combination of in-plane and out-of-plane electrical switching, coupled with ab initio studies, we have discovered that the epitaxy from the substrate imposes a magnetoelastic anisotropy on the spin cycloid, which establishes preferred cycloid propagation directions. The energy landscape of the cycloid is shaped by both the ferroelectric degree of freedom and strain-induced anisotropy, restricting the spin spiral propagation vector to changes to specific switching events.
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Affiliation(s)
- Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Guy Moore
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Shiyu Zhou
- Department of Physics, Brown University, Providence, RI, USA
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Sajid Husain
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics and Astronomy, Department of Materials Science and Nanoengineering, Rice Advanced Materials Institute, Rice University, Houston, TX, USA
- Department of Chemistry, Rice University, Houston, TX, USA
| | - Kristin A Persson
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sinéad Griffin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lucas Caretta
- School of Engineering, Brown University, Providence, RI, USA
| | - Paul Stevenson
- Department of Physics, Northeastern University, Boston, MA, USA.
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics and Astronomy, Department of Materials Science and Nanoengineering, Rice Advanced Materials Institute, Rice University, Houston, TX, USA
- Department of Physics, University of California, Berkeley, CA, USA
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4
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Meisenheimer P, Ghosal A, Hoglund E, Wang Z, Behera P, Gómez-Ortiz F, Kavle P, Karapetrova E, García-Fernández P, Martin LW, Raja A, Chen LQ, Hopkins PE, Junquera J, Ramesh R. Interlayer Coupling Controlled Ordering and Phases in Polar Vortex Superlattices. Nano Lett 2024; 24:2972-2979. [PMID: 38416567 PMCID: PMC10941248 DOI: 10.1021/acs.nanolett.3c03738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 03/01/2024]
Abstract
The recent discovery of polar topological structures has opened the door for exciting physics and emergent properties. There is, however, little methodology to engineer stability and ordering in these systems, properties of interest for engineering emergent functionalities. Notably, when the surface area is extended to arbitrary thicknesses, the topological polar texture becomes unstable. Here we show that this instability of the phase is due to electrical coupling between successive layers. We demonstrate that this electrical coupling is indicative of an effective screening length in the dielectric, similar to the conductor-ferroelectric interface. Controlling the electrostatics of the superlattice interfaces, the system can be tuned between a pure topological vortex state and a mixed classical-topological phase. This coupling also enables engineering coherency among the vortices, not only tuning the bulk phase diagram but also enabling the emergence of a 3D lattice of polar textures.
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Affiliation(s)
- Peter Meisenheimer
- Department
of Materials Science and Engineering, University
of California, Berkeley, California 94720, United States
| | - Arundhati Ghosal
- Department
of Physics, University of California, Berkeley, California 94720, United States
| | - Eric Hoglund
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37830, United States
- Department
of Materials Science and Engineering, Department of Mechanical and Aerospace
Engineering, Department of Physics, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Zhiyang Wang
- Department
of Materials Science and Engineering, Penn
State University, State
College, Pennsylvania 16801, United States
| | - Piush Behera
- Department
of Materials Science and Engineering, University
of California, Berkeley, California 94720, United States
| | - Fernando Gómez-Ortiz
- Departamento
de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Avenida de los Castros s/n, 39005 Santander, Spain
| | - Pravin Kavle
- Department
of Materials Science and Engineering, University
of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Evguenia Karapetrova
- Advanced
Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Pablo García-Fernández
- Departamento
de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Avenida de los Castros s/n, 39005 Santander, Spain
| | - Lane W. Martin
- Department
of Materials Science and Engineering, University
of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Department
of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
| | - Archana Raja
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Long-Qing Chen
- Department
of Materials Science and Engineering, Penn
State University, State
College, Pennsylvania 16801, United States
| | - Patrick E. Hopkins
- Department
of Materials Science and Engineering, Department of Mechanical and Aerospace
Engineering, Department of Physics, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Javier Junquera
- Departamento
de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Avenida de los Castros s/n, 39005 Santander, Spain
| | - Ramamoorthy Ramesh
- Department
of Materials Science and Engineering, University
of California, Berkeley, California 94720, United States
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Department
of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
- Department
of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
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5
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Zhang H, Chen X, Wang T, Huang X, Chen X, Shao YT, Meng F, Meisenheimer P, N'Diaye A, Klewe C, Shafer P, Pan H, Jia Y, Crommie MF, Martin LW, Yao J, Qiu Z, Muller DA, Birgeneau RJ, Ramesh R. Room-Temperature, Current-Induced Magnetization Self-Switching in A Van Der Waals Ferromagnet. Adv Mater 2024; 36:e2308555. [PMID: 38016700 DOI: 10.1002/adma.202308555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/30/2023] [Indexed: 11/30/2023]
Abstract
2D layered materials with broken inversion symmetry are being extensively pursued as spin source layers to realize high-efficiency magnetic switching. Such low-symmetry layered systems are, however, scarce. In addition, most layered magnets with perpendicular magnetic anisotropy show a low Curie temperature. Here, the experimental observation of spin-orbit torque magnetization self-switching at room temperature in a layered polar ferromagnetic metal, Fe2.5 Co2.5 GeTe2 is reported. The spin-orbit torque is generated from the broken inversion symmetry along the c-axis of the crystal. These results provide a direct pathway toward applicable 2D spintronic devices.
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Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
| | - Fanhao Meng
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Alpha N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yanli Jia
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Michael F Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Departments of Materials Science and NanoEngineering, Chemistry, and Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, 14853, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
- Department of Physics and Astronomy, Department of Materials Science and Nanoengineering, Rice University, Houston, TX, 77005, USA
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6
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Vaz DC, Lin CC, Plombon JJ, Choi WY, Groen I, Arango IC, Chuvilin A, Hueso LE, Nikonov DE, Li H, Debashis P, Clendenning SB, Gosavi TA, Huang YL, Prasad B, Ramesh R, Vecchiola A, Bibes M, Bouzehouane K, Fusil S, Garcia V, Young IA, Casanova F. Voltage-based magnetization switching and reading in magnetoelectric spin-orbit nanodevices. Nat Commun 2024; 15:1902. [PMID: 38429273 PMCID: PMC10907725 DOI: 10.1038/s41467-024-45868-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/06/2024] [Indexed: 03/03/2024] Open
Abstract
As CMOS technologies face challenges in dimensional and voltage scaling, the demand for novel logic devices has never been greater, with spin-based devices offering scaling potential, at the cost of significantly high switching energies. Alternatively, magnetoelectric materials are predicted to enable low-power magnetization control, a solution with limited device-level results. Here, we demonstrate voltage-based magnetization switching and reading in nanodevices at room temperature, enabled by exchange coupling between multiferroic BiFeO3 and ferromagnetic CoFe, for writing, and spin-to-charge current conversion between CoFe and Pt, for reading. We show that, upon the electrical switching of the BiFeO3, the magnetization of the CoFe can be reversed, giving rise to different voltage outputs. Through additional microscopy techniques, magnetization reversal is linked with the polarization state and antiferromagnetic cycloid propagation direction in the BiFeO3. This study constitutes the building block for magnetoelectric spin-orbit logic, opening a new avenue for low-power beyond-CMOS technologies.
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Affiliation(s)
- Diogo C Vaz
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain.
| | - Chia-Ching Lin
- Components Research, Intel Corp., Hillsboro, OR, 97124, USA
| | - John J Plombon
- Components Research, Intel Corp., Hillsboro, OR, 97124, USA
| | - Won Young Choi
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain
- VanaM Inc., 21-1 Doshin-ro 4-gil, Yeongdeungpo-gu, Seoul, Republic of Korea
| | - Inge Groen
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain
| | - Isabel C Arango
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain
| | - Andrey Chuvilin
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Basque Country, Spain
| | - Luis E Hueso
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Basque Country, Spain
| | | | - Hai Li
- Components Research, Intel Corp., Hillsboro, OR, 97124, USA
| | | | | | - Tanay A Gosavi
- Components Research, Intel Corp., Hillsboro, OR, 97124, USA
| | - Yen-Lin Huang
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Bhagwati Prasad
- Materials Engineering Department, Indian Institute of Science, Bengaluru, 560012, Karnataka, India
| | - Ramamoorthy Ramesh
- Department of Physics, University of California, Berkeley, CA, 94720, USA
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Aymeric Vecchiola
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Manuel Bibes
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Karim Bouzehouane
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Stephane Fusil
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Vincent Garcia
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Ian A Young
- Components Research, Intel Corp., Hillsboro, OR, 97124, USA
| | - Fèlix Casanova
- CIC nanoGUNE BRTA, 20018, Donostia-San Sebastian, Basque Country, Spain.
- IKERBASQUE, Basque Foundation for Science, 48009, Bilbao, Basque Country, Spain.
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7
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Husain S, Harris I, Gao G, Li X, Meisenheimer P, Shi C, Kavle P, Choi CH, Kim TY, Kang D, Behera P, Perrodin D, Guo H, M Tour J, Han Y, Martin LW, Yao Z, Ramesh R. Low-temperature grapho-epitaxial La-substituted BiFeO 3 on metallic perovskite. Nat Commun 2024; 15:479. [PMID: 38212317 PMCID: PMC10784590 DOI: 10.1038/s41467-024-44728-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/03/2024] [Indexed: 01/13/2024] Open
Abstract
Bismuth ferrite has garnered considerable attention as a promising candidate for magnetoelectric spin-orbit coupled logic-in-memory. As model systems, epitaxial BiFeO3 thin films have typically been deposited at relatively high temperatures (650-800 °C), higher than allowed for direct integration with silicon-CMOS platforms. Here, we circumvent this problem by growing lanthanum-substituted BiFeO3 at 450 °C (which is reasonably compatible with silicon-CMOS integration) on epitaxial BaPb0.75Bi0.25O3 electrodes. Notwithstanding the large lattice mismatch between the La-BiFeO3, BaPb0.75Bi0.25O3, and SrTiO3 (001) substrates, all the layers in the heterostructures are well ordered with a [001] texture. Polarization mapping using atomic resolution STEM imaging and vector mapping established the short-range polarization ordering in the low temperature grown La-BiFeO3. Current-voltage, pulsed-switching, fatigue, and retention measurements follow the characteristic behavior of high-temperature grown La-BiFeO3, where SrRuO3 typically serves as the metallic electrode. These results provide a possible route for realizing epitaxial multiferroics on complex-oxide buffer layers at low temperatures and opens the door for potential silicon-CMOS integration.
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Affiliation(s)
- Sajid Husain
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Isaac Harris
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Guanhui Gao
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Xinyan Li
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Chuqiao Shi
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Pravin Kavle
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Chi Hun Choi
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Tae Yeon Kim
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Deokyoung Kang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Piush Behera
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Didier Perrodin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hua Guo
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - James M Tour
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
- Department of Chemistry, Rice University, Houston, TX, 77005, USA
| | - Yimo Han
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA
| | - Lane W Martin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA
| | - Zhi Yao
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Ramamoorthy Ramesh
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Physics, University of California, Berkeley, CA, 94720, USA.
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
- Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA.
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8
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Lupi E, Wexler RB, Meyers D, Zahradnik A, Jiang Y, Susarla S, Ramesh R, Martin LW, Rappe AM. Engineering Relaxor Behavior in (BaTiO 3 ) n /(SrTiO 3 ) n Superlattices. Adv Mater 2023; 35:e2302012. [PMID: 37433562 DOI: 10.1002/adma.202302012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/02/2023] [Accepted: 07/10/2023] [Indexed: 07/13/2023]
Abstract
Complex-oxide superlattices provide a pathway to numerous emergent phenomena because of the juxtaposition of disparate properties and the strong interfacial interactions in these unit-cell-precise structures. This is particularly true in superlattices of ferroelectric and dielectric materials, wherein new forms of ferroelectricity, exotic dipolar textures, and distinctive domain structures can be produced. Here, relaxor-like behavior, typically associated with the chemical inhomogeneity and complexity of solid solutions, is observed in (BaTiO3 )n /(SrTiO3 )n (n = 4-20 unit cells) superlattices. Dielectric studies and subsequent Vogel-Fulcher analysis show significant frequency dispersion of the dielectric maximum across a range of periodicities, with enhanced dielectric constant and more robust relaxor behavior for smaller period n. Bond-valence molecular-dynamics simulations predict the relaxor-like behavior observed experimentally, and interpretations of the polar patterns via 2D discrete-wavelet transforms in shorter-period superlattices suggest that the relaxor behavior arises from shape variations of the dipolar configurations, in contrast to frozen antipolar stripe domains in longer-period superlattices (n = 16). Moreover, the size and shape of the dipolar configurations are tuned by superlattice periodicity, thus providing a definitive design strategy to use superlattice layering to create relaxor-like behavior which may expand the ability to control desired properties in these complex systems.
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Affiliation(s)
- Eduardo Lupi
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Robert B Wexler
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104-6323, USA
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Derek Meyers
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Department of Physics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Anton Zahradnik
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Yizhe Jiang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andrew M Rappe
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104-6323, USA
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9
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Ramesh R, Thimonier C, Desgranges S, Faugeras V, Coulouvrat F, Laurent J, Marrelec G, Contino-Pépin C, Urbach W, Tribet C, Taulier N. Acoustic Droplet Vaporization of Perfluorohexane Emulsions Induced by Heterogeneous Nucleation at an Ultrasonic Frequency of 1.1 MHz. Langmuir 2023; 39:15716-15729. [PMID: 37889478 DOI: 10.1021/acs.langmuir.3c02272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Droplets made of liquid perfluorocarbon undergo a phase transition and transform into microbubbles when triggered by ultrasound of intensity beyond a critical threshold; this mechanism is called acoustic droplet vaporization (ADV). It has been shown that if the intensity of the signal coming from high ultrasonic harmonics are sufficiently high, superharmonic focusing is the mechanism leading to ADV for large droplets (>3 μm) and high frequencies (>1.5 MHz). In such a scenario, ADV is initiated due to a nucleus occurring at a specific location inside the droplet volume. But the question on what induces ADV in the case of nanometer-sized droplets and/or at low ultrasonic frequencies (<1.5 MHz) still remains. We investigated ADV of perfluorohexane (PFH) nano- and microdroplets at a frequency of 1.1 MHz and at conditions where there is no superharmonic focusing. Three types of droplets produced by microfluidics were studied: plain PFH droplets, PFH droplets containing many nanometer-sized water droplets, and droplets made of a PFH corona encapsulating a single micron-sized water droplet. The probability to observe a vaporization event was measured as a function of acoustic pressure. As our experiments were performed on droplet suspensions containing a population of monodisperse droplets, we developed a statistical model to extrapolate, from our experimental curves, the ADV pressure thresholds in the case where only one droplet would be insonified. We observed that the value of ADV pressure threshold decreases as the radius of a plain PFH droplet increases. This value was further reduced when a PFH droplet encapsulates a micron-sized water droplet, while the encapsulation of many nanometer-sized water droplets did not modify the threshold. These results cannot be explained by a model of homogeneous nucleation. However, we developed a heterogeneous nucleation model, where the nucleus appears at the surface in contact with PFH, that successfully predicts our experimental ADV results.
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Affiliation(s)
- R Ramesh
- CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Sorbonne Université, F-75006 Paris, France
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris Cité, F-75005 Paris, France
| | - C Thimonier
- CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Sorbonne Université, F-75006 Paris, France
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris Cité, F-75005 Paris, France
- Département de Chimie, P.A.S.T.E.U.R., École Normale Supérieure, Université PSL, Sorbonne Université, CNRS, 75005 Paris, France
| | - S Desgranges
- Équipe Systèmes Amphiphiles Bioactifs et Formulations Eco-compatibles, UPRI, Avignon Université, 84000 Avignon, France
| | - V Faugeras
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris Cité, F-75005 Paris, France
| | - F Coulouvrat
- Institut Jean le Rond d'Alembert, CNRS, Sorbonne Université, 4 Place Jussieu, 75005 Paris, France
| | - J Laurent
- Laboratoire de Physique et Mécanique des Milieux Hétérogénes, CNRS, ESPCI Paris, PSL Research University, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - G Marrelec
- CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Sorbonne Université, F-75006 Paris, France
| | - C Contino-Pépin
- Équipe Systèmes Amphiphiles Bioactifs et Formulations Eco-compatibles, UPRI, Avignon Université, 84000 Avignon, France
| | - W Urbach
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - C Tribet
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - N Taulier
- CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Sorbonne Université, F-75006 Paris, France
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10
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Priya S, Murali A, Mohan S, Lakshminarayanan A, Sekar S, Ramesh R, Devendiran M, Han SS. In vitro anti-prostate adenocarcinoma and lung cancer studies of phenoxyaniline- block-poly(methyl methacrylate) based nanocomposites via controlled radical polymerization. Nanoscale Adv 2023; 5:5870-5879. [PMID: 37881709 PMCID: PMC10597550 DOI: 10.1039/d3na00644a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/14/2023] [Indexed: 10/27/2023]
Abstract
A phenoxyaniline-based macroinitiator is utilized for the first time in order to produce phenoxyaniline-block-poly(methyl methacrylate) composites through single electron transfer-living radical polymerization (SET-LRP) under mild conditions. A different weight percentage of Cloisite 93A is added into the polymer mixtures in order to increase their biochemical properties. The prepared block copolymer nanocomposites are characterized using ATR-IR, UV-vis-spectroscopy, XRD, Raman, TGA, DSC, a particle size analyzer, contact angle measurements and SEM in order to characterize their structural, thermal, surface and morphological properties. Further, the developed polymeric nanocomposites are successfully applied in two different cancer cell lines (prostate adenocarcinoma and lung cancer), which show excellent anticancer properties. Also, acridine orange/ethidium bromide (AO/EtBr) dual staining is performed, which causes drastic cell death by apoptosis in both A549 and PC-3 cell lines, which indicated that the prepared polymeric nanocomposites effectively inhibit the cell proliferation and induce the apoptosis in both the cancer cells. Here nanoclay is used for cancer treatment because of its complete water solubility, which essentially causes the formation of a cationic complex between the clay and drug through electrostatic interactions. Hence, the exchange of ions between the clay and other ions in the biological environment leads to inhibition of the proliferation of prostate adenocarcinoma and lung cancer cells in the system.
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Affiliation(s)
- Sahariya Priya
- School of Chemical Engineering, Yeungnam University 280 Daehak-Ro Gyeongsan Gyeongbuk 38541 Republic of Korea
| | - Adhigan Murali
- School for Advanced Research in Petrochemicals (SARP)- ARSTPS, Central Institute of Petrochemicals Engineering & Technology (CIPET), Govt. of India Chennai 600032 India
| | - Sakar Mohan
- Centre for Nano and Material Sciences, Jain University Bangalore 562112 Karnataka India
| | - A Lakshminarayanan
- Department of Pharmacology, Indira Medical College and Hospitals Tiruvallur Tamilnadu 631 203 India
| | - S Sekar
- School for Advanced Research in Petrochemicals (SARP)- ARSTPS, Central Institute of Petrochemicals Engineering & Technology (CIPET), Govt. of India Chennai 600032 India
| | - R Ramesh
- Department of Chemical Engineering, School of Mechanical, Chemical and Material Engineering, Adama Science and Technology University, Adama P.O. Box: 1888 Adama Ethiopia
| | - M Devendiran
- Vels Institute of Science Technology and Advanced Studies (VISTAS) Pallavaram Chennai 117 India
| | - Sung Soo Han
- School of Chemical Engineering, Yeungnam University 280 Daehak-Ro Gyeongsan Gyeongbuk 38541 Republic of Korea
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11
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Nagarajan V, Ramesh R, Chandiramouli R. N-Nitrosamine sensing properties of novel penta-silicane nanosheets-a first-principles outlook. J Mol Model 2023; 29:309. [PMID: 37688608 DOI: 10.1007/s00894-023-05711-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 08/29/2023] [Indexed: 09/11/2023]
Abstract
CONTEXT N-Nitrosamine is one of the highly toxic carcinogenic compounds that are found almost in the entire environment. In the present work, novel penta-silicene (penta-Si) and penta-silicane (penta-HSi) are utilised to sense the N-nitrosamine in the air environment. Initially, structural firmness of penta-Si and penta-HSi is confirmed using cohesive energy. Subsequently, the electronic properties of penta-Si and penta-HSi are discussed with the aid of electronic band structure and projected density of states (PDOS) maps. The calculated band gap of penta-Si and penta-HSi is 0.251 eV and 3.117 eV, correspondingly. Mainly, the adsorption property of N-nitrosamine on the penta-Si and penta-HSi is studied based on adsorption energy, Mulliken population analysis along with relative energy gap changes. The computed adsorption energy range is in physisorption (- 0.101 to - 0.619 eV), which recommends that the proposed penta-Si and penta-HSi can be employed as a promising sensor to detect the N-nitrosamine in the air environment. METHODS The structural, electronic and adsorption behaviour of N-nitrosamine on penta-Si and penta-HSi are studied based on the density functional theory (DFT) approach. The hybrid generalized gradient approximation (GGA) with Becke's three-parameter (B3) + Lee-Yang-Parr (LYP) exchange correlation functional is used to optimise the base material. All calculations in the present work are carried out in Quantum-ATK-Atomistic Simulation Software.
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Affiliation(s)
- V Nagarajan
- School of Electrical & Electronics Engineering, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613 401, India
| | - R Ramesh
- School of Electrical & Electronics Engineering, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613 401, India
| | - R Chandiramouli
- School of Electrical & Electronics Engineering, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, 613 401, India.
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12
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Susarla S, Hsu S, Gómez-Ortiz F, García-Fernández P, Savitzky BH, Das S, Behera P, Junquera J, Ercius P, Ramesh R, Ophus C. The emergence of three-dimensional chiral domain walls in polar vortices. Nat Commun 2023; 14:4465. [PMID: 37491370 PMCID: PMC10368707 DOI: 10.1038/s41467-023-40009-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Chirality or handedness of a material can be used as an order parameter to uncover the emergent electronic properties for quantum information science. Conventionally, chirality is found in naturally occurring biomolecules and magnetic materials. Chirality can be engineered in a topological polar vortex ferroelectric/dielectric system via atomic-scale symmetry-breaking operations. We use four-dimensional scanning transmission electron microscopy (4D-STEM) to map out the topology-driven three-dimensional domain walls, where the handedness of two neighbor topological domains change or remain the same. The nature of the domain walls is governed by the interplay of the local perpendicular (lateral) and parallel (axial) polarization with respect to the tubular vortex structures. Unique symmetry-breaking operations and the finite nature of domain walls result in a triple point formation at the junction of chiral and achiral domain walls. The unconventional nature of the domain walls with triple point pairs may result in unique electrostatic and magnetic properties potentially useful for quantum sensing applications.
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Affiliation(s)
- Sandhya Susarla
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA.
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, 94720, CA, USA.
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, 85280, AZ, USA.
| | - Shanglin Hsu
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, 94720, CA, USA
| | - Fernando Gómez-Ortiz
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional Santander, Santander, 39005, Spain
| | - Pablo García-Fernández
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional Santander, Santander, 39005, Spain
| | - Benjamin H Savitzky
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Piush Behera
- Department of Materials Science & Engineering, University of California, Berkeley, 94720, CA, USA
| | - Javier Junquera
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional Santander, Santander, 39005, Spain
| | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA
| | - Ramamoorthy Ramesh
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA.
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, 94720, CA, USA.
- Department of Physics, University of California, Berkeley, Berkeley, 94720, CA, USA.
- Department of Physics, Rice University, Houston, 77005, TX, USA.
- Department of Materials Science and Nanoengineering, Houston, 77005, TX, USA.
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA.
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13
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Addiego C, Zorn JA, Gao W, Das S, Guo J, Qu C, Zhao L, Martin LW, Ramesh R, Chen LQ, Pan X. Multiscale Electric-Field Imaging of Polarization Vortex Structures in PbTiO3/SrTiO3 Superlattices. Microsc Microanal 2023; 29:1620-1621. [PMID: 37613804 DOI: 10.1093/micmic/ozad067.832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Christopher Addiego
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Jacob A Zorn
- Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA, United States
| | - Wenpei Gao
- Department of Materials Science and Engineering, University of California, Irvine, CA, United States
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States
| | - Jiaqi Guo
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Chengqing Qu
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Liming Zhao
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States
| | - Long-Qing Chen
- Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA, United States
| | - Xiaoqing Pan
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
- Department of Materials Science and Engineering, University of California, Irvine, CA, United States
- Irvine Materials Research Institute, University of California, Irvine, CA, United States
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14
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Yalisove R, Meisenheimer P, Zhang H, Chen R, Chen X, Birgeneau RJ, Yao J, Ramesh R, Scott MC. Characterizing Magnetic Skyrmion Ordering and Dis-Ordering in the Presence of Crystalline Dislocations using Lorentz Transmission Electron Microscopy. Microsc Microanal 2023; 29:1648-1649. [PMID: 37613948 DOI: 10.1093/micmic/ozad067.848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Reed Yalisove
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
- Lawrence Berkeley National Lab, National Center for Electron Microscopy, Berkeley, CA, United States
| | - Peter Meisenheimer
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
| | - Hongrui Zhang
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
| | - Rui Chen
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
- Lawrence Berkeley National Lab, Materials Sciences Division, Berkeley, CA, United States
| | - Xiang Chen
- Lawrence Berkeley National Lab, Materials Sciences Division, Berkeley, CA, United States
- University of California, Department of Physics, Berkeley, CA, United States
| | - Robert J Birgeneau
- Lawrence Berkeley National Lab, Materials Sciences Division, Berkeley, CA, United States
- University of California, Department of Physics, Berkeley, CA, United States
| | - Jie Yao
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
- Lawrence Berkeley National Lab, Materials Sciences Division, Berkeley, CA, United States
| | - Ramamoorthy Ramesh
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
| | - Mary C Scott
- University of California, Berkeley, Department of Materials Science and Engineering, Berkeley, CA, United States
- Lawrence Berkeley National Lab, National Center for Electron Microscopy, Berkeley, CA, United States
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15
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Martis J, Susarla S, Rayabharam A, Su C, Paule T, Pelz P, Huff C, Xu X, Li HK, Jaikissoon M, Chen V, Pop E, Saraswat K, Zettl A, Aluru NR, Ramesh R, Ercius P, Majumdar A. Imaging the electron charge density in monolayer MoS 2 at the Ångstrom scale. Nat Commun 2023; 14:4363. [PMID: 37474521 PMCID: PMC10359339 DOI: 10.1038/s41467-023-39304-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 06/06/2023] [Indexed: 07/22/2023] Open
Abstract
Four-dimensional scanning transmission electron microscopy (4D-STEM) has recently gained widespread attention for its ability to image atomic electric fields with sub-Ångstrom spatial resolution. These electric field maps represent the integrated effect of the nucleus, core electrons and valence electrons, and separating their contributions is non-trivial. In this paper, we utilized simultaneously acquired 4D-STEM center of mass (CoM) images and annular dark field (ADF) images to determine the projected electron charge density in monolayer MoS2. We evaluate the contributions of both the core electrons and the valence electrons to the derived electron charge density; however, due to blurring by the probe shape, the valence electron contribution forms a nearly featureless background while most of the spatial modulation comes from the core electrons. Our findings highlight the importance of probe shape in interpreting charge densities derived from 4D-STEM and the need for smaller electron probes.
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Affiliation(s)
- Joel Martis
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Sandhya Susarla
- The National Center for Electron Microscopy (NCEM), The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Archith Rayabharam
- Department of Mechanical Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Cong Su
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, USA
- Kavli Energy NanoScience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Timothy Paule
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, USA
- Kavli Energy NanoScience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Philipp Pelz
- The National Center for Electron Microscopy (NCEM), The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Institute of Micro- and Nanostructure Research & Center for Nanoanalysis and Electron Microscopy (CENEM), Department of Materials Science, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Cassandra Huff
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Xintong Xu
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Hao-Kun Li
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Marc Jaikissoon
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Victoria Chen
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Eric Pop
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Krishna Saraswat
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Alex Zettl
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, USA
- Kavli Energy NanoScience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Narayana R Aluru
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Ramamoorthy Ramesh
- Department of Physics, University of California Berkeley, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, USA
| | - Peter Ercius
- The National Center for Electron Microscopy (NCEM), The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Arun Majumdar
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA.
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16
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Das S, McCarter MR, Gómez-Ortiz F, Tang YL, Hong Z, Ghosh A, Shafer P, García-Fernández P, Junquera J, Martin LW, Ramesh R. Pure Chiral Polar Vortex Phase in PbTiO 3/SrTiO 3 Superlattices with Tunable Circular Dichroism. Nano Lett 2023. [PMID: 37449842 DOI: 10.1021/acs.nanolett.3c01744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
Nontrivial polarization textures have been demonstrated in ferroelectric/dielectric superlattices, where the electrostatic, elastic, and different gradient energies compete in a delicate balance. When PbTiO3/SrTiO3 superlattices are grown on DyScO3, the coexistence of ferroelectric domains and vortex structure is observed for n = 12-20 unit cells. Here, we report an approach to achieve single-phase vortex structures in superlattices by controlling the epitaxial strain using Sr1.04Al0.12Ga0.35Ta0.50O3 substrates. The domain width follows Kittel's law with the thickness of the ferroelectric PbTiO3 layers. A phase transition from vortex to a disordered phase with temperature is characterized by the correlation length. Resonant soft X-ray diffraction circular dichroism at the titanium L-edge reveals enhanced chirality with the thickness of the ferroelectric layer. These results are supported by second-principles simulations, which demonstrate that the integrated helicity increases with n. The stabilization of chiral single-phase polar vortices in ferroelectric/dielectric superlattices can enable novel optoelectronic devices with enhanced ferroelectric-light interaction.
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Affiliation(s)
- Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Margaret R McCarter
- Department of Materials Science & Engineering, University of California, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
| | - Fernando Gómez-Ortiz
- Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Avenida de los Castros s/n, E-39005 Santander, Spain
| | - Yun-Long Tang
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Zijian Hong
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Anirban Ghosh
- Department of Materials Science & Engineering, University of California, Berkeley, California 94720, United States
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Pablo García-Fernández
- Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Avenida de los Castros s/n, E-39005 Santander, Spain
| | - Javier Junquera
- Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Avenida de los Castros s/n, E-39005 Santander, Spain
| | - Lane W Martin
- Department of Materials Science & Engineering, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ramamoorthy Ramesh
- Department of Materials Science & Engineering, University of California, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Materials Science and Nanoengineering, Department of Physics and Astronomy, Rice University, Houston, Texas 77251, United States
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17
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Meisenheimer P, Zhang H, Raftrey D, Chen X, Shao YT, Chan YT, Yalisove R, Chen R, Yao J, Scott MC, Wu W, Muller DA, Fischer P, Birgeneau RJ, Ramesh R. Ordering of room-temperature magnetic skyrmions in a polar van der Waals magnet. Nat Commun 2023; 14:3744. [PMID: 37353526 DOI: 10.1038/s41467-023-39442-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023] Open
Abstract
Control and understanding of ensembles of skyrmions is important for realization of future technologies. In particular, the order-disorder transition associated with the 2D lattice of magnetic skyrmions can have significant implications for transport and other dynamic functionalities. To date, skyrmion ensembles have been primarily studied in bulk crystals, or as isolated skyrmions in thin film devices. Here, we investigate the condensation of the skyrmion phase at room temperature and zero field in a polar, van der Waals magnet. We demonstrate that we can engineer an ordered skyrmion crystal through structural confinement on the μm scale, showing control over this order-disorder transition on scales relevant for device applications.
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Affiliation(s)
- Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - David Raftrey
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Ying-Ting Chan
- Department of Physics, Rutgers University, New Brunswick, NJ, USA
| | - Reed Yalisove
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Mary C Scott
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Weida Wu
- Department of Physics, Rutgers University, New Brunswick, NJ, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
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18
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Behera P, Parsonnet E, Gómez-Ortiz F, Srikrishna V, Meisenheimer P, Susarla S, Kavle P, Caretta L, Wu Y, Tian Z, Fernandez A, Martin LW, Das S, Junquera J, Hong Z, Ramesh R. Emergent Ferroelectric Switching Behavior from Polar Vortex Lattice. Adv Mater 2023; 35:e2208367. [PMID: 36930962 DOI: 10.1002/adma.202208367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 03/08/2023] [Indexed: 06/09/2023]
Abstract
Topologically protected polar textures have provided a rich playground for the exploration of novel, emergent phenomena. Recent discoveries indicate that ferroelectric vortices and skyrmions not only host properties markedly different from traditional ferroelectrics, but also that these properties can be harnessed for unique memory devices. Using a combination of capacitor-based capacitance measurements and computational models, it is demonstrated that polar vortices in dielectric-ferroelectric-dielectric trilayers exhibit classical ferroelectric bi-stability together with the existence of low-field metastable polarization states. This behavior is directly tied to the in-plane vortex ordering, and it is shown that it can be used as a new method of non-destructive readout-out of the poled state.
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Affiliation(s)
- Piush Behera
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eric Parsonnet
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Fernando Gómez-Ortiz
- Department of Earth Sciences and Condensed Matter Physics, Universidad de Cantabria, Cantabria Campus Internacional, 39005, Santander, Spain
| | - Vishantak Srikrishna
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Sandhya Susarla
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Pravin Kavle
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Yongjun Wu
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Zishen Tian
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Abel Fernandez
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Javier Junquera
- Department of Earth Sciences and Condensed Matter Physics, Universidad de Cantabria, Cantabria Campus Internacional, 39005, Santander, Spain
| | - Zijian Hong
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
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19
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Zeltmann SE, Hsu SL, Brown HG, Susarla S, Ramesh R, Minor AM, Ophus C. Uncovering polar vortex structures by inversion of multiple scattering with a stacked Bloch wave model. Ultramicroscopy 2023; 250:113732. [PMID: 37087909 DOI: 10.1016/j.ultramic.2023.113732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 03/21/2023] [Accepted: 04/03/2023] [Indexed: 04/25/2023]
Abstract
Nanobeam electron diffraction can probe local structural properties of complex crystalline materials including phase, orientation, tilt, strain, and polarization. Ideally, each diffraction pattern from a projected area of a few unit cells would produce a clear Bragg diffraction pattern, where the reciprocal lattice vectors can be measured from the spacing of the diffracted spots, and the spot intensities are equal to the square of the structure factor amplitudes. However, many samples are too thick for this simple interpretation of their diffraction patterns, as multiple scattering of the electron beam can produce a highly nonlinear relationship between the spot intensities and the underlying structure. Here, we develop a stacked Bloch wave method to model the diffracted intensities from thick samples with structure that varies along the electron beam. Our method reduces the large parameter space of electron scattering to just a few structural variables per probe position, making it fast enough to apply to very large fields of view. We apply our method to SrTiO3/PbTiO3/SrTiO3 multilayer samples, and successfully disentangle specimen tilt from the mean polarization of the PbTiO3 layers. We elucidate the structure of complex vortex topologies in the PbTiO3 layers, demonstrating the promise of our method to extract material properties from thick samples.
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Affiliation(s)
- Steven E Zeltmann
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States of America.
| | - Shang-Lin Hsu
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
| | - Hamish G Brown
- Ian Holmes Imaging Centre, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - Sandhya Susarla
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, United States of America
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States of America
| | - Andrew M Minor
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States of America; National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America.
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20
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Xu R, Crust KJ, Harbola V, Arras R, Patel KY, Prosandeev S, Cao H, Shao YT, Behera P, Caretta L, Kim WJ, Khandelwal A, Acharya M, Wang MM, Liu Y, Barnard ES, Raja A, Martin LW, Gu XW, Zhou H, Ramesh R, Muller DA, Bellaiche L, Hwang HY. Size-Induced Ferroelectricity in Antiferroelectric Oxide Membranes. Adv Mater 2023; 35:e2210562. [PMID: 36739113 DOI: 10.1002/adma.202210562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/06/2023] [Indexed: 05/17/2023]
Abstract
Despite extensive studies on size effects in ferroelectrics, how structures and properties evolve in antiferroelectrics with reduced dimensions still remains elusive. Given the enormous potential of utilizing antiferroelectrics for high-energy-density storage applications, understanding their size effects will provide key information for optimizing device performances at small scales. Here, the fundamental intrinsic size dependence of antiferroelectricity in lead-free NaNbO3 membranes is investigated. Via a wide range of experimental and theoretical approaches, an intriguing antiferroelectric-to-ferroelectric transition upon reducing membrane thickness is probed. This size effect leads to a ferroelectric single-phase below 40 nm, as well as a mixed-phase state with ferroelectric and antiferroelectric orders coexisting above this critical thickness. Furthermore, it is shown that the antiferroelectric and ferroelectric orders are electrically switchable. First-principle calculations further reveal that the observed transition is driven by the structural distortion arising from the membrane surface. This work provides direct experimental evidence for intrinsic size-driven scaling in antiferroelectrics and demonstrates enormous potential of utilizing size effects to drive emergent properties in environmentally benign lead-free oxides with the membrane platform.
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Affiliation(s)
- Ruijuan Xu
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27606, USA
| | - Kevin J Crust
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Physics, Stanford University, Stanford, CA, 94305, USA
| | - Varun Harbola
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Physics, Stanford University, Stanford, CA, 94305, USA
| | - Rémi Arras
- CEMES, Université de Toulouse, CNRS, UPS, 29 rue Jeanne Marvig, F-31055, Toulouse, France
| | - Kinnary Y Patel
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Sergey Prosandeev
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Hui Cao
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Yu-Tsun Shao
- Department of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
| | - Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- School of Engineering, Brown University, Providence, RI, 02912, USA
| | - Woo Jin Kim
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Aarushi Khandelwal
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Megha Acharya
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Melody M Wang
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Yin Liu
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27606, USA
| | - Edward S Barnard
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Archana Raja
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - X Wendy Gu
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Hua Zhou
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Nanoengineering, Department of Physics and Astronomy, Rice University, Houston, TX, 77251, USA
| | - David A Muller
- Department of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Harold Y Hwang
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
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21
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Mugilarasan M, Karthik R, Robin RS, Subbareddy B, Hariharan G, Anandavelu I, Jinoj TPS, Purvaja R, Ramesh R. Anthropogenic marine litter: An approach to environmental quality for India's southeastern Arabian Sea coast. Sci Total Environ 2023; 866:161363. [PMID: 36610620 DOI: 10.1016/j.scitotenv.2022.161363] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/21/2022] [Accepted: 12/30/2022] [Indexed: 06/17/2023]
Abstract
Anthropogenic marine litter (AML), mainly plastic, is a global concern that is persistent and widespread. To prevent and mitigate this threat, we need to understand the magnitude and source of AML. There is limited knowledge about AML pollution on the Indian Coast. In this context, the present study examined the distribution, abundance, typology, and beach quality based on AML along 22 beaches on the southeastern coast of the Arabian Sea. A total of 4911 AML items were classified into 9 categories, weighing 16.79 kg, and retrieved from a total area of 8000 m2. The mean abundance and weight of AML in the current study were 0.45 ± 0.34 items/m2 and 1.53 ± 0.92 g/m2, respectively. Thottapally showed the most abundant AML among the studied beaches with 0.96 items/m2, followed by Azheekkal with 0.73 items/m2. Plastic, being the most common item, accounts for 77.6 % of all items and has a mean density of 0.35 items/m2 comprising hard plastic (22 %), thermocol (13 %), food wrappers (7 %), cigarette butts (7 %), plastic rope (6 %), and plastic cutlery (6 %). Hazardous anthropogenic litter (HAL) was maximum at Thottapally (17.71 %; 85 out of 480 items collected). Based on the cleanliness of beaches, they are graded "moderately clean" (63 %) by the General Index (GI), "clean" (54 %), and "moderately clean" (40 %) as calculated by the Clean Coast Index (CCI). Hazardous Anthropogenic Beach Litter Index (HABLI) classifies 72 % of beaches as "moderately safe", while the Environmental Status Index (ESI) rates 68 % of beaches as "mediocre". Besides, model simulations demonstrated the pathways of AML propagation, which correlate to the littoral and coastal current flow patterns over the region. Land-based activities were the crucial factors influencing AML distribution. The study highlighted the need for effective regional litter management strategies, policy instruments for the litter impact pathways, economic, regulatory, and behavioural management tools, which were also discussed.
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Affiliation(s)
- M Mugilarasan
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R Karthik
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R S Robin
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India.
| | - B Subbareddy
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - G Hariharan
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - I Anandavelu
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - T P S Jinoj
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai 600 025, India
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22
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Gopi CVVM, Ramesh R, Vinodh R, Alzahmi S, Obaidat IM. Facile Synthesis of Battery-Type CuMn 2O 4 Nanosheet Arrays on Ni Foam as an Efficient Binder-Free Electrode Material for High-Rate Supercapacitors. Nanomaterials (Basel) 2023; 13:1125. [PMID: 36986018 PMCID: PMC10058770 DOI: 10.3390/nano13061125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 06/18/2023]
Abstract
The development of battery-type electrode materials with hierarchical nanostructures has recently gained considerable attention in high-rate hybrid supercapacitors. For the first time, in the present study novel hierarchical CuMn2O4 nanosheet arrays (NSAs) nanostructures are developed using a one-step hydrothermal route on a nickel foam substrate and utilized as an enhanced battery-type electrode material for supercapacitors without the need of binders or conducting polymer additives. X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques are used to study the phase, structural, and morphological characteristics of the CuMn2O4 electrode. SEM and TEM studies show that CuMn2O4 exhibits a nanosheet array morphology. According to the electrochemical data, CuMn2O4 NSAs give a Faradic battery-type redox activity that differs from the behavior of carbon-related materials (such as activated carbon, reduced graphene oxide, graphene, etc.). The battery-type CuMn2O4 NSAs electrode showed an excellent specific capacity of 125.56 mA h g-1 at 1 A g-1 with a remarkable rate capability of 84.1%, superb cycling stability of 92.15% over 5000 cycles, good mechanical stability and flexibility, and low internal resistance at the interface of electrode and electrolyte. Due to their excellent electrochemical properties, high-performance CuMn2O4 NSAs-like structures are prospective battery-type electrodes for high-rate supercapacitors.
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Affiliation(s)
- Chandu V. V. Muralee Gopi
- Department of Electrical Engineering, University of Sharjah, Sharjah P.O. Box 27272, United Arab Emirates
| | - R. Ramesh
- Department of Chemical Engineering, School of Mechanical, Chemical and Materials Engineering, Adama Science and Technology University, Adama P.O. Box 1888, Ethiopia
| | - Rajangam Vinodh
- Green Hydrogen Lab (GH2Lab), Institute for Hydrogen Research (IHR), Université du Québec à Trois-Rivières (UQTR), 3351 Boulevard des Forges, Trois-Rivières, QC G9A 5H7, Canada
| | - Salem Alzahmi
- Department of Chemical & Petroleum Engineering, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- National Water and Energy Center, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Ihab M. Obaidat
- National Water and Energy Center, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Department of Physics, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
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23
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Mamidala HP, Ganguly D, Purvaja R, Singh G, Das S, Rao MN, Kazip Ys A, Arumugam K, Ramesh R. Interspecific variations in leaf litter decomposition and nutrient release from tropical mangroves. J Environ Manage 2023; 328:116902. [PMID: 36508978 DOI: 10.1016/j.jenvman.2022.116902] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/08/2022] [Accepted: 11/26/2022] [Indexed: 06/17/2023]
Abstract
Efficient nutrient cycling through decomposition of leaf litter often regulates the high productivity and subsequent carbon sequestration of mangrove ecosystems along the land-ocean boundary. To understand the characteristics and the potentials of mangrove leaf litter in supplying organic carbon and nutrients to the coastal waters, four major mangrove species (A. officinalis, R. mucronata, H. littoralis and S. apetala) of Bhitarkanika mangrove forest, Odisha, India, were examined in controlled environmental conditions. Half-life time (t0.5), estimated for decomposition of those mangrove leaf litter materials ranged from 18 to 52 days. During the incubation experiment, organic carbon from mangrove leaf litter was released primarily through physical processes and was available for heterotrophic respiration. Among the four species, leaf litter of S. apetala with the lowest initial C/N ratios, released organic carbon with low molecular weight (labile substances) that has a relatively higher potential to support the aquatic food web. On the contrary, leaf litter of R. mucronata released organic material with relatively higher molecular weight (humic substances, higher aromaticity), which revealed its superior non-labile characteristics in this unique environment. The mean total heterotrophic bacterial (THB) population in the incubation was around nine-fold higher than the control. THB population growth and Chromophoric Dissolved Organic Matter (CDOM) spectral data further suggested the rapid release of highly labile and recalcitrant carbon from S. apetala and R. mucronata (between 7th and 21st day of incubation), respectively. The mean litter fall from the Bhitarkanika mangrove forest was estimated to be 11.32 ± 1.57 Mg ha-1 y-1 and its corresponding carbon content was 5.43 ± 0.75 Mg C ha-1. The study revealed the role of leaf litter leachates as an important food source to microbial communities in the adjacent coastal waters, in addition to a potential carbon sequesterer through long-term burial in mangrove soil and export to the deep sea.
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Affiliation(s)
- Harikrishna Prasad Mamidala
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - D Ganguly
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - R Purvaja
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - Gurmeet Singh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - Subhajit Das
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - M Nageswar Rao
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - Armoury Kazip Ys
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - K Arumugam
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
| | - R Ramesh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
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24
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Caretta L, Shao YT, Yu J, Mei AB, Grosso BF, Dai C, Behera P, Lee D, McCarter M, Parsonnet E, K P H, Xue F, Guo X, Barnard ES, Ganschow S, Hong Z, Raja A, Martin LW, Chen LQ, Fiebig M, Lai K, Spaldin NA, Muller DA, Schlom DG, Ramesh R. Non-volatile electric-field control of inversion symmetry. Nat Mater 2023; 22:207-215. [PMID: 36536139 DOI: 10.1038/s41563-022-01412-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
Competition between ground states at phase boundaries can lead to significant changes in properties under stimuli, particularly when these ground states have different crystal symmetries. A key challenge is to stabilize and control the coexistence of symmetry-distinct phases. Using BiFeO3 layers confined between layers of dielectric TbScO3 as a model system, we stabilize the mixed-phase coexistence of centrosymmetric and non-centrosymmetric BiFeO3 phases at room temperature with antipolar, insulating and polar semiconducting behaviour, respectively. Application of orthogonal in-plane electric (polar) fields results in reversible non-volatile interconversion between the two phases, hence removing and introducing centrosymmetry. Counterintuitively, we find that an electric field 'erases' polarization, resulting from the anisotropy in octahedral tilts introduced by the interweaving TbScO3 layers. Consequently, this interconversion between centrosymmetric and non-centrosymmetric phases generates changes in the non-linear optical response of over three orders of magnitude, resistivity of over five orders of magnitude and control of microscopic polar order. Our work establishes a platform for cross-functional devices that take advantage of changes in optical, electrical and ferroic responses, and demonstrates octahedral tilts as an important order parameter in materials interface design.
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Affiliation(s)
- Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- School of Engineering, Brown University, Providence, RI, USA.
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Jia Yu
- Department of Physics, University of Texas, Austin, TX, USA
| | - Antonio B Mei
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | | | - Cheng Dai
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Daehun Lee
- Department of Physics, University of Texas, Austin, TX, USA
| | | | - Eric Parsonnet
- Department of Physics, University of California, Berkeley, CA, USA
| | - Harikrishnan K P
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Fei Xue
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Xiangwei Guo
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China
- Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, China
| | - Edward S Barnard
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Zijian Hong
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Manfred Fiebig
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Keji Lai
- Department of Physics, University of Texas, Austin, TX, USA
| | | | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
- Leibniz-Institut für Kristallzüchtung, Berlin, Germany
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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25
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Ramesh R, N S S, V Rao P. Case report on pre-orthodontic trainer in a 9-year-old child with 12 months follow up. IJPedoR 2023. [DOI: 10.56501/intjpedorehab.v8i1.712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND: Pre-fabricated myofunctional appliances for early orthodontic therapy have been designed specifically for the care of children at the time of mixed dentition in growing adolescents with class II division 1 malocclusions. Sophisticated prefabricated removable functional appliances known as pre-orthodontic trainers have been shown to train the orofacial musculature, thus correcting malocclusions.
CASE DESCRIPTION: This is a case report of 9-year-old boy diagnosed as Class II division 1 malocclusion with protruded upper anterior teeth, constricted upper arch, space loss in lower arch and Class 2 molar relation on side. Functional treatment approach was decided using pre orthodontic T4K trainer for 12 months. At the end of this phase of treatment, improvements have been evaluated with lateral cephalograms superimposition between T1 and T2.
DISCUSSION: Class II orthopaedic treatment along with the use of functional appliances by early interception assist in addressing the concerns with soft tissues, muscles, mouth respiration, and bruxism. The pre orthodontic trainer allowed a good dento-skeletal result as it had a major effect on the masticatory muscles after 12 months application which helped in obtaining a good esthetic outcome for the patient.
CONCLUSIONS: The use of prefabricated functional appliance in children can be an advantageous method for early treatment of class II malocclusions with functional patterns as these devices influences masticatory muscle which help in molding the facial tissues and a viable alternative to braces for treating malocclusions in children because it stimulates the development of the dental arches transversely to stop the progression of the malocclusion. Therefore, when a lack of transverse development is discovered at a young age, this appliance is an invaluable tool for enhancing dental arch development, interceptive management of malocclusion, and oral habits.
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26
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Saravanakumar C, Neethu CS, Purvaja R, Sunantha G, Robin RS, Ramesh R. Networking and co-occurrence of virulent and multidrug resistant environmental bacteria in different aquatic systems: A gap in MDR-virulence transfer? Sci Total Environ 2023; 857:159221. [PMID: 36206910 DOI: 10.1016/j.scitotenv.2022.159221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/21/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Co-occurrence of resistance and virulence is often overlooked in aquatic bacteria as environmental reservoirs, while transmission of these characteristics to clinically significant strains present unforeseen problems in future. In this investigation, environmental bacteria identified concurrently from multiple aquatic habitats viz., groundwater, canal, river and coastal waters were profiled for antibiotic resistance, metal tolerance, virulence factors and genes coding for these determinants. Strains from polluted river and canal exhibited higher resistance and virulence, especially Pseudomonas gessardii and P. fluorescens displayed high antibiotic resistance index (ARI > 0.6-0.8) with Alkaline Protease and Phospholipase production. Opportunistic pathogens including Vibrio parahaemolyticus, V. alginolyticus, V. vulnificus, Corynebacterium and Comamonas testosteroni expressed all three virulence factors with relatively low resistance. However, V. vulnificus and V. alginolyticus exhibited multiclass antibiotic resistance (5/6 classes). Metagenomic analysis revealed that genes corresponding to beta-lactam resistance were significantly higher (p < 0.05) in freshwater than seawater, while multidrug resistance gene were higher (p < 0.05) in seawater. In all aquatic bodies, abundant virulence genes belonged to secretion system proteins followed by motility related genes. Culturable bacteria revealed differential distribution of positive and negative correlation between 31 targeted genes with expressed resistance and virulence. Among Acinetobacter, significant positive correlation was found between Phospholipase production, other virulence genes (OVGs) and resistance to DNA Synthesis Inhibitors (DSI). In Pseudomonas, positive correlation was detected between toxin genes (toxA, eta, hlyA and stx) and resistance to cell wall synthesis inhibitors (CSI) as well as with OVGs and adhesion genes (eae, afa, papC and papA). Network analysis displayed unique clustering of genes ncc, arsB, strA, merA and intI dominated by non-pathogens and distinct clustering of genes pho, erm, nfsA, trh, lasB, tdh and invA by Vibrio. This investigation extends insight on co-occurring resistance and virulence in aquatic reservoir bacteria that could pose serious threats to public health in future.
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Affiliation(s)
- C Saravanakumar
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - C S Neethu
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - G Sunantha
- Chulalongkorn University of Engineering, Department of Engineering, Bangkok 10400, Thailand
| | - R S Robin
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India.
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27
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Parthiban A, Sachithanandam V, Sarangapany S, Misra R, Muthukrishnan P, Jeyakumar TC, Purvaja R, Ramesh R. Green synthesis of gold nanoparticles using quercetin biomolecule from mangrove plant, Ceriops tagal: Assessment of antiproliferative properties, cellular uptake and DFT studies. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Balachandar K, Viswanathan C, Robin RS, Abhilash KR, Sankar R, Deepak Samuel V, Purvaja R, Ramesh R. Benthic foraminifera as an environmental proxy for pollutants along the coast of Chennai, India. Chemosphere 2023; 310:136824. [PMID: 36241111 DOI: 10.1016/j.chemosphere.2022.136824] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 09/21/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Benthic foraminifera are increasingly used as an indicator of environmental disturbance. Their sensitivities to pollutants can be reflected by changes in assemblage, which can provide useful information about ecosystem health. This study aimed to investigate the impact of organic and inorganic pollutants on the benthic ecology of the Chennai coast, with a focus on the 2017 oil spill caused by the collision of two ships. Sediment samples collected from five distinct zones along the coast were analysed for pollutants such as polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPH), heavy metals (Cr, Cd, Pb) and total organic carbon (TOC). The maximum concentrations of Cr (137 μg/g), Cd (6.93 μg/g) and Pb (34.2 μg/g), as well as TPH (84.3 μg/g) and PAHs (227 ng/g), were observed. A total of 47 species of foraminifera were identified in this study, of which 12 were morphologically abnormal. In the low-impact zone, the species diversity index (H') was higher. TPH and PAH concentrations were positively associated with abnormal species. Pollution-resistant foraminifera species include Ammonia tepida, Elphidium discoidale, and Quinqueloculina lamarckiana, while opportunistic foraminifera include Pararotalia curryi, Nonionella stella, Rosalina globularis, and Spirillina vivipara. PAHs and heavy metals were adversely correlated with foraminiferal abundance, while TPH was positively correlated. To assess the response of the benthic ecosystem to hydrocarbon pollution, indices such as the Foraminiferal Index of Environmental Impact (FIEI), Exponential (H'bc) index and the Foraminiferal Abnormality Index (FAI) were used as environmental health proxies. FIEI, exp(H'bc) and FAI values show the impact of hydrocarbon pollution to an extent along the northern Chennai coast.
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Affiliation(s)
- K Balachandar
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
| | - C Viswanathan
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
| | - R S Robin
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
| | - K R Abhilash
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
| | - R Sankar
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
| | - V Deepak Samuel
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India.
| | - R Purvaja
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, Tamil Nadu, India
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29
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Susarla S, Naik MH, Blach DD, Zipfel J, Taniguchi T, Watanabe K, Huang L, Ramesh R, da Jornada FH, Louie SG, Ercius P, Raja A. Hyperspectral imaging of exciton confinement within a moiré unit cell with a subnanometer electron probe. Science 2022; 378:1235-1239. [PMID: 36520893 DOI: 10.1126/science.add9294] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Electronic and optical excitations in two-dimensional systems are distinctly sensitive to the presence of a moiré superlattice. We used cryogenic transmission electron microscopy and spectroscopy to simultaneously image the structural reconstruction and associated localization of the lowest-energy intralayer exciton in a rotationally aligned WS2-WSe2 moiré superlattice. In conjunction with optical spectroscopy and ab initio calculations, we determined that the exciton center-of-mass wave function is confined to a radius of approximately 2 nanometers around the highest-energy stacking site in the moiré unit cell. Our results provide direct evidence that atomic reconstructions lead to the strongly confining moiré potentials and that engineering strain at the nanoscale will enable new types of excitonic lattices.
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Affiliation(s)
- Sandhya Susarla
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Mit H Naik
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Daria D Blach
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Jonas Zipfel
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Ramamoorthy Ramesh
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA.,Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Felipe H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Steven G Louie
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Peter Ercius
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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30
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McCarter MR, Kim KT, Stoica VA, Das S, Klewe C, Donoway EP, Burn DM, Shafer P, Rodolakis F, Gonçalves MAP, Gómez-Ortiz F, Íñiguez J, García-Fernández P, Junquera J, Lovesey SW, van der Laan G, Park SY, Freeland JW, Martin LW, Lee DR, Ramesh R. Structural Chirality of Polar Skyrmions Probed by Resonant Elastic X-Ray Scattering. Phys Rev Lett 2022; 129:247601. [PMID: 36563236 DOI: 10.1103/physrevlett.129.247601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/08/2022] [Accepted: 10/23/2022] [Indexed: 06/17/2023]
Abstract
An escalating challenge in condensed-matter research is the characterization of emergent order-parameter nanostructures such as ferroelectric and ferromagnetic skyrmions. Their small length scales coupled with complex, three-dimensional polarization or spin structures makes them demanding to trace out fully. Resonant elastic x-ray scattering (REXS) has emerged as a technique to study chirality in spin textures such as skyrmions and domain walls. It has, however, been used to a considerably lesser extent to study analogous features in ferroelectrics. Here, we present a framework for modeling REXS from an arbitrary arrangement of charge quadrupole moments, which can be applied to nanostructures in materials such as ferroelectrics. With this, we demonstrate how extended reciprocal space scans using REXS with circularly polarized x rays can probe the three-dimensional structure and chirality of polar skyrmions. Measurements, bolstered by quantitative scattering calculations, show that polar skyrmions of mixed chirality coexist, and that REXS allows valuation of relative fractions of right- and left-handed skyrmions. Our quantitative analysis of the structure and chirality of polar skyrmions highlights the capability of REXS for establishing complex topological structures toward future application exploits.
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Affiliation(s)
- Margaret R McCarter
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Kook Tae Kim
- Department of Physics, Soongsil University, Seoul 06978, Korea
| | - Vladimir A Stoica
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
- Department of Materials Science and Engineering, Pennsylvania State University, Pennsylvania 16802, USA
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Elizabeth P Donoway
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - David M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Fanny Rodolakis
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Mauro A P Gonçalves
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague 8, Czech Republic
| | - Fernando Gómez-Ortiz
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, 39005 Santander, Spain
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxemburg
- Department of Physics and Materials Science, University of Luxembourg, Rue du Brill 41, L-4422 Belvaux, Luxembourg
| | - Pablo García-Fernández
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, 39005 Santander, Spain
| | - Javier Junquera
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, 39005 Santander, Spain
| | - Stephen W Lovesey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
- Department of Physics, Oxford University, Oxford OX1 3PU, United Kingdom
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Se Young Park
- Department of Physics, Soongsil University, Seoul 06978, Korea
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Dong Ryeol Lee
- Department of Physics, Soongsil University, Seoul 06978, Korea
| | - Ramamoorthy Ramesh
- Department of Physics, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Deepan R, Ramesh R. Prognostic Value Of Right Ventricle Free Wall Strain In Patients With Acute Decompensated Heart Failure. Indian Heart J 2022. [DOI: 10.1016/j.ihj.2022.10.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Paul V, Ramesh R, Sreeja P, Jarin T, Sujith Kumar PS, Ansar S, Ashraf GA, Pandey S, Said Z. Hybridization of long short-term memory with Sparrow Search Optimization model for water quality index prediction. Chemosphere 2022; 307:135762. [PMID: 35863408 DOI: 10.1016/j.chemosphere.2022.135762] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/09/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Water quality (WQ) analysis is a critical stage in water resource management and should be handled immediately in order to control pollutants that could have a negative influence on the ecosystem. The dramatic increase in population, the use of fertilizers and pesticides, and the industrial revolution have resulted in severe effects on the WQ environment. As a result, the prediction of WQ greatly helped to monitor water pollution. Accurate prediction of WQ is the foundation of managing water environments and is of high importance for protecting water environment. WQ data presents in the form of multi-variate time-sequence dataset. It is clear that the accuracy of predicting WQ will be enhanced when the multi-variate relation and time sequence dataset of WQ are fully utilized. This article presents the Water Quality Prediction utilising Sparrow Search Optimization with Hybrid Long Short-Term Memory (WQP-SSHLSTM) model. The presented WQP-SSHLSTM model intends to examine the data and classify WQ into distinct classes. To achieve this, the presented WQP-SSHLSTM model undergoes data scaling process to scale the input data into uniform format. Followed by, a hybrid long short-term memory-deep belief network (LSTM-DBN) technique is employed for the recognition and classification of WQ. Moreover, Sparrow search optimization algorithm (SSOA) is utilized as a hyperparameter optimizer of the proposed DBN-LSTM model. For demonstrating the enhanced outcomes of the presented WQP-SSHLSTM model, a sequence of experiments has been performed and the outcomes are reviewed under distinct prospects. The WQP-SSHLSTM model has achieved 99.84 percent accuracy, which is the maximum attainable. The simulation outcomes ensured the enhanced outcomes of the WQP-SSHLSTM model on recent methods.
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Affiliation(s)
- Vince Paul
- Dept. of Computer Science and Engineering, Eranad Knowledge City Technical Campus, Kerala, India
| | - R Ramesh
- DCA, Cochin University of Science and Technology, Kerala, India
| | - P Sreeja
- Department of EEE, KMEA Engineering College, Kerala, India
| | - T Jarin
- Department of EEE, Jyothi Engineering College, Kerala, India.
| | - P S Sujith Kumar
- Ilahia College of Engineering and Technology, Muvattupuzha, Kerala, India
| | - Sabah Ansar
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh, 11433, Saudi Arabia
| | - Ghulam Abbas Ashraf
- Department of Physics, Zhejiang Normal University, Zhejiang, 321004, Jinhua, China.
| | - Sadanand Pandey
- Department of Chemistry, College of Natural Science, Yeungnam University, 280 Daehak-Ro, Gyeongsan, Gyeongbuk, 38541, Republic of Korea
| | - Zafar Said
- Department of Sustainable and Renewable Energy Engineering, University of Sharjah, 27272, Sharjah, United Arab Emirates; U.S.-Pakistan Center for Advanced Studies in Energy (USPCAS-E), National University of Sciences and Technology (NUST), Islamabad, Pakistan
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Sathyaprasad S, Krishnareddy MG, Vinod V, Das N, Ramesh R, Ilyas I. Comparative Evaluation of Fixed Functional Cantilever Space Maintainer and Fixed Nonfunctional Space Maintainer: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2022; 15:750-760. [PMID: 36866140 PMCID: PMC9973074 DOI: 10.5005/jp-journals-10005-2478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Background and objectives Effective way to prevent mesial drift after the early loss of primary first molars is by inserting a durable space maintainer. Several space maintainers are available; fixed nonfunctional (FNF) space maintainer (crown and loop) is commonly used when abutment teeth need full-coronal restoration. Disadvantages of crown and loop space maintainer are nonfunctional, nonesthetic, and fracture of solder loop. To overcome this drawback, new design of fixed functional cantilever (FFC) space maintainer (crown and pontic) using bis-acrly composite resin. The study evaluated the longevity and acceptance of an FFC and compared it with a FNF space maintainer. Materials and methods A total of 20 healthy children, aged 6-9 years, were selected having bilateral premature loss of lower deciduous first molars. FFC space maintainer in one quadrant and FNF space maintainer in the other was cemented. The subject's acceptance of treatment was checked using a visual analog scale after the treatment completion. Criteria for complication leading to the failure was assessed in both the designs in the 3rd, 6th, and 9th month. Cumulative success longevity was obtained at a 9 month evaluation. Results Patient acceptability was greater in group I (FFC) in comparison to group II (FNF). In group I, fracture of the crown and pontic was the common complication leading to failure, followed by attrition of the crown and loss of material due to abrasion. In group II, fracture of the solder joint was the common complication leading to failure, followed by slippage of the loop gingivally and cement loss. The longevity of groups I and II were 70 and 85%, respectively. Conclusion FFC can be considered a viable alternative to conventional FNF space maintainers. How to cite this article Sathyaprasad S, Krishnareddy MG, Vinod V, et al. Comparative Evaluation of Fixed Functional Cantilever Space Maintainer and Fixed Nonfunctional Space Maintainer: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2022;15(6):750-760.
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Affiliation(s)
- Savitha Sathyaprasad
- Department of Pedodontics and Preventive Dentistry, KVG Dental College and Hospital, Sullia, Karnataka, India
| | | | - Vinisha Vinod
- Department of Pedodontics and Preventive Dentistry, Kannur Dental College, Kannur, Kerala, India
| | - Nikhil Das
- Department of Pedodontics and Preventive Dentistry, JKKN Dental College and Hospital Komarapalayam, Tamil Nadu, India
| | - R Ramesh
- Department of Pedodontics and Preventive Dentistry, Saveetha Dental College, Chennai, Tamil Nadu, India
| | - Irfana Ilyas
- Pedodontic Practitioner at Mangalore Dental Clinic, Kasaragod, Kerala, India
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Ramesh R, Kayal S, Manivannan P, Choudhary A, Ganesan P, Sahadevan S, Dubashi B. 218P Prognostic role of apoptotic index in acute lymphoblastic leukemia. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.10.253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
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Neethu CS, Saravanakumar C, Purvaja R, Robin RS, Ramesh R. Arsenic resistance and horizontal gene transfer are associated with carbon and nitrogen enrichment in bacteria. Environ Pollut 2022; 311:119937. [PMID: 35977641 DOI: 10.1016/j.envpol.2022.119937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/14/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
Coastal waters are confluences receiving large amounts of point and non-point sources of pollution. An attempt was made to explore microbial community interactions in response to carbon, nitrogen and metal pollution. Additionally, experiments were designed to analyze the influence of these factors on horizontal gene transfer (HGT). Shift in bacterial diversity dynamics by arsenic stress and nutrient addition in coastal waters was explored by metagenomics of microcosm setups. Phylogenetic analysis revealed equal distribution of Gammaproteobacteria (29%) and Betaproteobacteria (28%) in control microcosm. This proportional diversity from control switched to unique distribution of Gammaproteobacteria (44.5%)> Flavobacteria (17.7%)> Bacteriodia (11.92%)> Betaproteobacteria (11.52%) in microcosm supplemented with carbon, nitrogen and metal (C + N + M). Among metal-stressed systems, alpha diversity analysis indicated highest diversity of genera in C + N + M followed by N + M > C+M> metal alone. Arsenic and ampicillin sensitive E. coli XL1 blue and environmental strains (Vibrio tubiashii W85 and E. coli W101) were tested for efficiency of uptake of plasmid (P) pUCminusMCS (arsBRampR) under varying stress conditions. Transformation experiments revealed that combined effect of carbon, nitrogen and metal on horizontal gene transfer (HGT) was significantly higher (p < 0.01) than individual factors. The effect of carbon on HGT was proved to be superior to nitrogen under metal stressed conditions. Presence of arsenic in experimental setups (P + M, P + N + M and P + C + M) enhanced the HGT compared to non-metal counterparts supplemented with carbon or nitrogen. Arsenic resistant bacterial isolates (n = 200) were tested for the ability to utilize various carbon and nitrogen substrates and distinct positive correlation (p < 0.001) was found between arsenic resistance and utilization of urea and nitrate. However, evident positive correlation was not found between carbon sources and arsenic resistance. Our findings suggest that carbon and nitrogen pollution in aquatic habitats under arsenic stress determine the microbial community dynamics and critically influence uptake of genetic material from the surrounding environment.
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Affiliation(s)
- C S Neethu
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - C Saravanakumar
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R S Robin
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management (NCSCM), Ministry of Environment, Forest and Climate Change (MoEFCC), Chennai 600025, India.
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Ramesh R, Judy MV. Distributed Clustering Approach by Apache Pyspark Based on Seer for Clinical Data. INT J PATTERN RECOGN 2022. [DOI: 10.1142/s0218001422400067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Parsonnet E, Caretta L, Nagarajan V, Zhang H, Taghinejad H, Behera P, Huang X, Kavle P, Fernandez A, Nikonov D, Li H, Young I, Analytis J, Ramesh R. Nonvolatile Electric Field Control of Thermal Magnons in the Absence of an Applied Magnetic Field. Phys Rev Lett 2022; 129:087601. [PMID: 36053684 DOI: 10.1103/physrevlett.129.087601] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/07/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Spin transport through magnetic insulators has been demonstrated in a variety of materials and is an emerging pathway for next-generation spin-based computing. To modulate spin transport in these systems, one typically applies a sufficiently strong magnetic field to allow for deterministic control of magnetic order. Here, we make use of the well-known multiferroic magnetoelectric, BiFeO_{3}, to demonstrate nonvolatile, hysteretic, electric-field control of thermally excited magnon current in the absence of an applied magnetic field. These findings are an important step toward magnon-based devices, where electric-field-only control is highly desirable.
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Affiliation(s)
- Eric Parsonnet
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Vikram Nagarajan
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Hossein Taghinejad
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Pravin Kavle
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Abel Fernandez
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Dmitri Nikonov
- Components Research, Intel Corporation, Hillsboro, Oregon 97124, USA
| | - Hai Li
- Components Research, Intel Corporation, Hillsboro, Oregon 97124, USA
| | - Ian Young
- Components Research, Intel Corporation, Hillsboro, Oregon 97124, USA
| | - James Analytis
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Ramamoorthy Ramesh
- Department of Physics, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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K.G. S, Benoy M, Duraimurugan J, Prabhu S, Siranjeevi R, Ramesh R, Suresh Kumar G, Shkir M. Synergistic effect of NiS/g-C3N4 nanocomposite for high‐performance asymmetric supercapacitors. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hariharan G, Purvaja R, Anandavelu I, Robin RS, Ramesh R. Ingestion and toxic impacts of weathered polyethylene (wPE) microplastics and stress defensive responses in whiteleg shrimp (Penaeus vannamei). Chemosphere 2022; 300:134487. [PMID: 35381267 DOI: 10.1016/j.chemosphere.2022.134487] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 03/17/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Weathered plastic litter is recognized as hazardous secondary microplastics(MPs) in the coastal and marine ecosystems, which are of high concern due to their greater impact on the environment. The present study aims to elucidate the impacts of environmentally weathered polyethylene (wPE) MPs on ingestion, growth and enzymatic responses in Penaeus vannamei. The Penaeus vannamei was chronically exposed to five varying concentration (0.1 mg-0.5 mg) of wPE particles in the size range between 43 and 32 μm for a period of 25days, followed by 5days depuration. At the end of exposure, a considerable number of wPE particles were observed from <2 to 14 per individual organism. However, around 60% of the wPE particles were removed after the depuration phase. The toxic exposure on P. vannamei resulted in significant changes in the enzymatic and growth responses with increasing concentration and duration. In addition, growth assessment confirmed that wPE exposure inhibited the growth of organism, and the effect was particularly evident at increasing concentrations and prolonged exposure. Also observed an elevated levels of lipid peroxidation, glutathione-S-transferases, whereas lower levels of reduced-glutathione and catalase at all exposed concentrations. This study confirmed that the ingestion of wPE was completely influenced by exposure duration, rather than the concentrations of administered. The present biomarker assay might act as an appropriate oxidative stress index for wPE toxicity. Findings of this study is useful in providing the basic biological information for environmental risk assessments of MPs, which are of high concern due to the rising input of microplastics into the environment.
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Affiliation(s)
- G Hariharan
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, 600025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, 600025, India
| | - I Anandavelu
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, 600025, India
| | - R S Robin
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, 600025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, 600025, India.
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Karthik R, Robin RS, Purvaja R, Karthikeyan V, Subbareddy B, Balachandar K, Hariharan G, Ganguly D, Samuel VD, Jinoj TPS, Ramesh R. Microplastic pollution in fragile coastal ecosystems with special reference to the X-Press Pearl maritime disaster, southeast coast of India. Environ Pollut 2022; 305:119297. [PMID: 35421552 DOI: 10.1016/j.envpol.2022.119297] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/22/2022] [Accepted: 04/10/2022] [Indexed: 06/14/2023]
Abstract
Microplastics (MPs) are a global environmental concern and pose a serious threat to marine ecosystems. This study aimed to determine the abundance and distribution of MPs in beach sediments (12 beaches), marine biota (6 beaches) and the influence of microbes on MPs degradation in eco-sensitive Palk Bay and Gulf of Mannar coast. The mean MP abundance 65.4 ± 39.8 particles/m2 in beach sediments; 0.19 ± 1.3 particles/individual fish and 0.22 ± 0.11 particles g-1 wet weight in barnacles. Polyethylene fragments (33.4%) and fibres (48%) were the most abundant MPs identified in sediments and finfish, respectively. Histopathological examination of fish has revealed health consequences such as respiratory system damage, epithelial degradation and enterocyte vacuolization. In addition, eight bacterial and seventeen fungal strains were isolated from the beached MPs. The results also indicated weathering of MPs due to microbial interactions. Model simulations helped in tracking the fate and transboundary landfall of spilled MPs across the Indian Ocean coastline after the X-Press Pearl disaster. Due to regional circulations induced by the monsoonal wind fields, a potential dispersal of pellets has occurred along the coast of Sri Lanka, but no landfall and ecological damage are predicted along the coast of India.
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Affiliation(s)
- R Karthik
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - R S Robin
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - R Purvaja
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - V Karthikeyan
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - B Subbareddy
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - K Balachandar
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - G Hariharan
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - D Ganguly
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - V D Samuel
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - T P S Jinoj
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India
| | - R Ramesh
- National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai, 600 025, India.
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Jiang Y, Parsonnet E, Qualls A, Zhao W, Susarla S, Pesquera D, Dasgupta A, Acharya M, Zhang H, Gosavi T, Lin CC, Nikonov DE, Li H, Young IA, Ramesh R, Martin LW. Enabling ultra-low-voltage switching in BaTiO 3. Nat Mater 2022; 21:779-785. [PMID: 35618823 DOI: 10.1038/s41563-022-01266-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
Single crystals of BaTiO3 exhibit small switching fields and energies, but thin-film performance is considerably worse, thus precluding their use in next-generation devices. Here, we demonstrate high-quality BaTiO3 thin films with nearly bulk-like properties. Thickness scaling provides access to the coercive voltages (<100 mV) and fields (<10 kV cm-1) required for future applications and results in a switching energy of <2 J cm-3 (corresponding to <2 aJ per bit in a 10 × 10 × 10 nm3 device). While reduction in film thickness reduces coercive voltage, it does so at the expense of remanent polarization. Depolarization fields impact polar state stability in thicker films but fortunately suppress the coercive field, thus driving a deviation from Janovec-Kay-Dunn scaling and enabling a constant coercive field for films <150 nm in thickness. Switching studies reveal fast speeds (switching times of ~2 ns for 25-nm-thick films with 5-µm-diameter capacitors) and a pathway to subnanosecond switching. Finally, integration of BaTiO3 thin films onto silicon substrates is shown. We also discuss what remains to be demonstrated to enable the use of these materials for next-generation devices.
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Affiliation(s)
- Y Jiang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - E Parsonnet
- Department of Physics, University of California, Berkeley, CA, USA
| | - A Qualls
- Department of Physics, University of California, Berkeley, CA, USA
| | - W Zhao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - S Susarla
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - D Pesquera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and BIST, Barcelona, Spain
| | - A Dasgupta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - M Acharya
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - H Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - T Gosavi
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - C-C Lin
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - D E Nikonov
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - H Li
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - I A Young
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - R Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - L W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Chen X, Shao YT, Chen R, Susarla S, Hogan T, He Y, Zhang H, Wang S, Yao J, Ercius P, Muller DA, Ramesh R, Birgeneau RJ. Pervasive beyond Room-Temperature Ferromagnetism in a Doped van der Waals Magnet. Phys Rev Lett 2022; 128:217203. [PMID: 35687434 DOI: 10.1103/physrevlett.128.217203] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
The existence of long-range magnetic order in low-dimensional magnetic systems, such as the quasi-two-dimensional van der Waals (vdW) magnets, has attracted intensive studies of new physical phenomena. The vdW Fe_{N}GeTe_{2} (N=3, 4, 5; FGT) family is exceptional, owing to its vast tunability of magnetic properties. In particular, a ferromagnetic ordering temperature (T_{C}) above room temperature at N=5 (F5GT) is observed. Here, our study shows that, by nickel (Ni) substitution of iron in F5GT, a record high T_{C}=478(6) K is achieved. Importantly, pervasive, beyond room-temperature ferromagnetism exists in almost the entire doping range of the phase diagram of Ni-F5GT. We argue that this striking observation in Ni-F5GT can be possibly due to several contributing factors, including increased 3D magnetic couplings due to the structural alterations.
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Affiliation(s)
- Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Rui Chen
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Tom Hogan
- Quantum Design, Inc., San Diego, California 92121, USA
| | - Yu He
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut, 06511, USA
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Siqi Wang
- NSF Nanoscale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA
| | - Jie Yao
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Peter Ercius
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA
| | - Ramamoorthy Ramesh
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
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Das S, Laguta V, Inzani K, Huang W, Liu J, Chatterjee R, McCarter MR, Susarla S, Ardavan A, Junquera J, Griffin SM, Ramesh R. Inherent Spin-Polarization Coupling in a Magnetoelectric Vortex. Nano Lett 2022; 22:3976-3982. [PMID: 35561341 DOI: 10.1021/acs.nanolett.2c00496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Solid-state materials are currently being explored as a platform for the manipulation of spins for spintronics and quantum information science. More broadly, a wide spectrum of ferroelectric materials, spanning from inorganic oxides to polymeric systems such as PVDF, present a different approach to explore quantum phenomena in which the spins are set and manipulated with electric fields. Using dilute Fe3+-doped ferroelectric PbTiO3-SrTiO3 superlattices as a model system, we demonstrate intrinsic spin-polarization control of spin directionality in complex ferroelectric vortices and skyrmions. Electron paramagnetic resonance (EPR) spectra show that the spins in the Fe3+ ion are strongly coupled to the local polarization and preferentially aligned perpendicular to the ferroelectric polar c axis in this complex vortex structure. The effect of polarization-spin directionality is corroborated by first-principles calculations, demonstrating the variation of the spin directionality with the polar texture and offering the potential for future quantum analogues of macroscopic magnetoelectric devices.
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Affiliation(s)
- Sujit Das
- Material Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Valentyn Laguta
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic
| | - Katherine Inzani
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Weichuan Huang
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
| | - Junjie Liu
- CAESR, Department of Physics, University of Oxford, The Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Ruchira Chatterjee
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Margaret R McCarter
- Department of Physics, University of California, Berkeley, California 94720, United States
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Arzhang Ardavan
- CAESR, Department of Physics, University of Oxford, The Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Javier Junquera
- Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, Avenida de los Castros s/n, E-39005 Santander, Spain
| | - Sinéad M Griffin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ramamoorthy Ramesh
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
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44
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Nimbalkar V, Snijesh V, Rajarajan S, Patil S, Anupama C, Ramesh R, Srinath B, Prabhu J. 46P Co-expression of GR with PR isoforms is associated with differential prognosis in estrogen receptor-positive breast cancer. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.03.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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45
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Cheema SS, Shanker N, Wang LC, Hsu CH, Hsu SL, Liao YH, San Jose M, Gomez J, Chakraborty W, Li W, Bae JH, Volkman SK, Kwon D, Rho Y, Pinelli G, Rastogi R, Pipitone D, Stull C, Cook M, Tyrrell B, Stoica VA, Zhang Z, Freeland JW, Tassone CJ, Mehta A, Saheli G, Thompson D, Suh DI, Koo WT, Nam KJ, Jung DJ, Song WB, Lin CH, Nam S, Heo J, Parihar N, Grigoropoulos CP, Shafer P, Fay P, Ramesh R, Mahapatra S, Ciston J, Datta S, Mohamed M, Hu C, Salahuddin S. Ultrathin ferroic HfO 2-ZrO 2 superlattice gate stack for advanced transistors. Nature 2022; 604:65-71. [PMID: 35388197 DOI: 10.1038/s41586-022-04425-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 01/14/2022] [Indexed: 11/09/2022]
Abstract
With the scaling of lateral dimensions in advanced transistors, an increased gate capacitance is desirable both to retain the control of the gate electrode over the channel and to reduce the operating voltage1. This led to a fundamental change in the gate stack in 2008, the incorporation of high-dielectric-constant HfO2 (ref. 2), which remains the material of choice to date. Here we report HfO2-ZrO2 superlattice heterostructures as a gate stack, stabilized with mixed ferroelectric-antiferroelectric order, directly integrated onto Si transistors, and scaled down to approximately 20 ångströms, the same gate oxide thickness required for high-performance transistors. The overall equivalent oxide thickness in metal-oxide-semiconductor capacitors is equivalent to an effective SiO2 thickness of approximately 6.5 ångströms. Such a low effective oxide thickness and the resulting large capacitance cannot be achieved in conventional HfO2-based high-dielectric-constant gate stacks without scavenging the interfacial SiO2, which has adverse effects on the electron transport and gate leakage current3. Accordingly, our gate stacks, which do not require such scavenging, provide substantially lower leakage current and no mobility degradation. This work demonstrates that ultrathin ferroic HfO2-ZrO2 multilayers, stabilized with competing ferroelectric-antiferroelectric order in the two-nanometre-thickness regime, provide a path towards advanced gate oxide stacks in electronic devices beyond conventional HfO2-based high-dielectric-constant materials.
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Affiliation(s)
- Suraj S Cheema
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA.
| | - Nirmaan Shanker
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Li-Chen Wang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Cheng-Hsiang Hsu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Shang-Lin Hsu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Yu-Hung Liao
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Matthew San Jose
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, USA
| | - Jorge Gomez
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, USA
| | - Wriddhi Chakraborty
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, USA
| | - Wenshen Li
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Jong-Ho Bae
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Steve K Volkman
- Applied Science and Technology, University of California, Berkeley, CA, USA
| | - Daewoong Kwon
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Yoonsoo Rho
- Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, CA, USA
| | - Gianni Pinelli
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Ravi Rastogi
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Dominick Pipitone
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Corey Stull
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Matthew Cook
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Brian Tyrrell
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Vladimir A Stoica
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA
| | - Zhan Zhang
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA
| | - Christopher J Tassone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Apurva Mehta
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | | | | | - Dong Ik Suh
- Research & Development Division, SK hynix, Icheon, Korea
| | - Won-Tae Koo
- Research & Development Division, SK hynix, Icheon, Korea
| | - Kab-Jin Nam
- Semiconductor R&D Center, Samsung Electronics, Gyeonggi-do, Korea
| | - Dong Jin Jung
- Semiconductor R&D Center, Samsung Electronics, Gyeonggi-do, Korea
| | - Woo-Bin Song
- Semiconductor R&D Center, Samsung Electronics, Gyeonggi-do, Korea
| | - Chung-Hsun Lin
- Logic Technology Development, Intel Corporation, Hillsboro, OR, USA
| | - Seunggeol Nam
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Korea
| | - Jinseong Heo
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Korea
| | - Narendra Parihar
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Costas P Grigoropoulos
- Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, CA, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Patrick Fay
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA.,Department of Physics, University of California, Berkeley, Berkeley, CA, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Souvik Mahapatra
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Jim Ciston
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Suman Datta
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, USA
| | - Mohamed Mohamed
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Chenming Hu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA
| | - Sayeef Salahuddin
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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46
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Zhang H, Raftrey D, Chan YT, Shao YT, Chen R, Chen X, Huang X, Reichanadter JT, Dong K, Susarla S, Caretta L, Chen Z, Yao J, Fischer P, Neaton JB, Wu W, Muller DA, Birgeneau RJ, Ramesh R. Room-temperature skyrmion lattice in a layered magnet (Fe 0.5Co 0.5) 5GeTe 2. Sci Adv 2022; 8:eabm7103. [PMID: 35319983 PMCID: PMC8942374 DOI: 10.1126/sciadv.abm7103] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/28/2022] [Indexed: 05/26/2023]
Abstract
Novel magnetic ground states have been stabilized in two-dimensional (2D) magnets such as skyrmions, with the potential next-generation information technology. Here, we report the experimental observation of a Néel-type skyrmion lattice at room temperature in a single-phase, layered 2D magnet, specifically a 50% Co-doped Fe5GeTe2 (FCGT) system. The thickness-dependent magnetic domain size follows Kittel's law. The static spin textures and spin dynamics in FCGT nanoflakes were studied by Lorentz electron microscopy, variable-temperature magnetic force microscopy, micromagnetic simulations, and magnetotransport measurements. Current-induced skyrmion lattice motion was observed at room temperature, with a threshold current density, jth = 1 × 106 A/cm2. This discovery of a skyrmion lattice at room temperature in a noncentrosymmetric material opens the way for layered device applications and provides an ideal platform for studies of topological and quantum effects in 2D.
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Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - David Raftrey
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Physics Department, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Ying-Ting Chan
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Jonathan T. Reichanadter
- Department of Electrical Engineering, University of California, Berkeley, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Kaichen Dong
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sandhya Susarla
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Zhen Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Physics Department, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Jeffrey B. Neaton
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
- Kavli Energy Nanosciences Institute at Berkeley, Berkeley, CA, USA
| | - Weida Wu
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - David A. Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA
| | - Robert J. Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
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47
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Shi Q, Parsonnet E, Cheng X, Fedorova N, Peng RC, Fernandez A, Qualls A, Huang X, Chang X, Zhang H, Pesquera D, Das S, Nikonov D, Young I, Chen LQ, Martin LW, Huang YL, Íñiguez J, Ramesh R. The role of lattice dynamics in ferroelectric switching. Nat Commun 2022; 13:1110. [PMID: 35236832 PMCID: PMC8891289 DOI: 10.1038/s41467-022-28622-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 02/03/2022] [Indexed: 11/10/2022] Open
Abstract
Reducing the switching energy of ferroelectric thin films remains an important goal in the pursuit of ultralow-power ferroelectric memory and logic devices. Here, we elucidate the fundamental role of lattice dynamics in ferroelectric switching by studying both freestanding bismuth ferrite (BiFeO3) membranes and films clamped to a substrate. We observe a distinct evolution of the ferroelectric domain pattern, from striped, 71° ferroelastic domains (spacing of ~100 nm) in clamped BiFeO3 films, to large (10’s of micrometers) 180° domains in freestanding films. By removing the constraints imposed by mechanical clamping from the substrate, we can realize a ~40% reduction of the switching voltage and a consequent ~60% improvement in the switching speed. Our findings highlight the importance of a dynamic clamping process occurring during switching, which impacts strain, ferroelectric, and ferrodistortive order parameters and plays a critical role in setting the energetics and dynamics of ferroelectric switching. Reducing the switching energy of ferroelectric films remains an important goal. Here, the authors elucidate the fundamental role of lattice dynamics in ferroelectric switching on both freestanding BiFeO3 membranes and films clamped to a substrate.
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Affiliation(s)
- Qiwu Shi
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. .,College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China.
| | - Eric Parsonnet
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Xiaoxing Cheng
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania, 16802, PA, USA
| | - Natalya Fedorova
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, L-4362, Esch/Alzette, Luxembourg
| | - Ren-Ci Peng
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Information and Engineering, Xi'an Jiaotong University, 710049, Xi'an, China.,School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710126, China
| | - Abel Fernandez
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Alexander Qualls
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xue Chang
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - David Pesquera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.,Material Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Dmitri Nikonov
- Components Research, Intel Corporation, Hillsboro, OR, 97142, USA
| | - Ian Young
- Components Research, Intel Corporation, Hillsboro, OR, 97142, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania, 16802, PA, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yen-Lin Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. .,Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, L-4362, Esch/Alzette, Luxembourg.,Department of Physics and Materials Science, University of Luxembourg, L-4422, Belvaux, Luxembourg
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. .,Department of Physics, University of California, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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48
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Megala S, Silambarasan A, Kanagesan S, Selvaraj M, Maadeswaran P, Ramesh R, Alam MM, Assiri MA. Interfacial coupling of CuWO4 nanoparticles on NiAl LDH as a novel photoctalyst for dissolved organic dye degradation. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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49
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Dai C, Stoica VA, Das S, Hong Z, Martin LW, Ramesh R, Freeland JW, Wen H, Gopalan V, Chen LQ. Tunable Nanoscale Evolution and Topological Phase Transitions of a Polar Vortex Supercrystal. Adv Mater 2022; 34:e2106401. [PMID: 34958699 DOI: 10.1002/adma.202106401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Understanding the phase transitions and domain evolutions of mesoscale topological structures in ferroic materials is critical to realizing their potential applications in next-generation high-performance storage devices. Here, the behaviors of a mesoscale supercrystal are studied with 3D nanoscale periodicity and rotational topology phases in a PbTiO3 /SrTiO3 (PTO/STO) superlattice under thermal and electrical stimuli using a combination of phase-field simulations and X-ray diffraction experiments. A phase diagram of temperature versus polar state is constructed, showing the formation of the supercrystal from a mixed vortex and a-twin state and a temperature-dependent erasing process of a supercrystal returning to a classical a-twin structure. Under an in-plane electric field bias at room temperature, the vortex topology of the supercrystal irreversibly transforms to a new type of stripe-like supercrystal. Under an out-of-plane electric field, the vortices inside the supercrystal undergo a topological phase transition to polar skyrmions. These results demonstrate the potential for the on-demand manipulation of polar topology and transformations in supercrystals using electric fields. The findings provide a theoretical understanding that may be utilized to guide the design and control of mesoscale polar structures and to explore novel polar structures in other systems and their topological nature.
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Affiliation(s)
- Cheng Dai
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Vladimir Alexandru Stoica
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Zijian Hong
- Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Haidan Wen
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Venkatraman Gopalan
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
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50
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Elumalai N, Prabhu S, Selvaraj M, Silambarasan A, Navaneethan M, Harish S, Ramu P, Ramesh R. Enhanced photocatalytic activity of ZnO hexagonal tube/r-GO composite on degradation of organic aqueous pollutant and study of charge transport properties. Chemosphere 2022; 291:132782. [PMID: 34748798 DOI: 10.1016/j.chemosphere.2021.132782] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 10/11/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
ZnO hexagonal tube and ZnO/r-GO nanocomposites were synthesized by hydrothermal method and the nanostructures were characterized by XRD, UV-DRS, PL, FTIR, FESEM, and TEM techniques. The main violet emission peak of the synthesized nanostructures is due to the transition between interstitial zinc and hole (valence band) of ZnO. The potential of ZnO/r-GO nanocomposite was evaluated using methyl orange (MO) and rhodamine-B (RhB), and the results were compared with the activity of synthesized ZnO nanostructures. More than 95% of MO and RhB were by ZnO/r-GO nanocomposite and it was found to be higher than that of ZnO hexagonal tube. The degradation MO and RhB were found to follow first-order kinetics and it has a rate constant of 7.68 × 10-2and 7.83 × 10-2 min-1, respectively. These results are mainly due to the enhanced charge transport property. Trapping experiments show that superoxide radical anion and hydroxide radicals are chief species responsible for the degradation of MO and RhB. The chemical stability of the nanocomposite was evaluated by cycle test experiments and it reveals that the catalyst can be reused up to few cycles without considerable loss of photocatalytic activity. This work affords a simple stratagem to integrate ZnO hexagonal tubes and r-GO nanosheets to construct effective catalysts for the degradation of organic compounds.
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Affiliation(s)
- N Elumalai
- Department of Physics, Government Arts College (Autonomous), Salem, 7, Tamil Nadu, India; Department of Physics, Periyar University, Salem, 11, Tamil Nadu, India
| | - S Prabhu
- Department of Physics, Periyar University, Salem, 11, Tamil Nadu, India
| | - M Selvaraj
- Department of Chemistry, Faculty of Science, King Khalid University, Abha, 61413, Saudi Arabia.
| | - A Silambarasan
- Department of Chemistry, Vivekanandha College of Arts and Sciences for Women (Autonomous), Elayampalayam, Namakkal, 637 205, Tamil Nadu, India.
| | - M Navaneethan
- Nanotechnology Research Centre, SRM Institute of Science and Technology, Kanchepuram, Tamil Nadu, India; Department of Physics and Nanotechnology, SRM Institute of Science and Technology, Kanchepuram, Tamil Nadu, India.
| | - S Harish
- Department of Physics and Nanotechnology, SRM Institute of Science and Technology, Kanchepuram, Tamil Nadu, India
| | - P Ramu
- Department of Physics, Government Arts College (Autonomous), Salem, 7, Tamil Nadu, India.
| | - R Ramesh
- Department of Physics, Periyar University, Salem, 11, Tamil Nadu, India.
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