1
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Jensen JH, Strømberg A, Breivik I, Penty A, Niño MA, Khaliq MW, Foerster M, Tufte G, Folven E. Clocked dynamics in artificial spin ice. Nat Commun 2024; 15:964. [PMID: 38302504 PMCID: PMC10834408 DOI: 10.1038/s41467-024-45319-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/19/2024] [Indexed: 02/03/2024] Open
Abstract
Artificial spin ice (ASI) are nanomagnetic metamaterials with a wide range of emergent properties. Through local interactions, the magnetization of the nanomagnets self-organize into extended magnetic domains. However, controlling when, where and how domains change has proven difficult, yet is crucial for technological applications. Here, we introduce astroid clocking, which offers significant control of ASI dynamics in both time and space. Astroid clocking unlocks a discrete, step-wise and gradual dynamical process within the metamaterial. Notably, our method employs global fields to selectively manipulate local features within the ASI. Sequences of these clock fields drive domain dynamics. We demonstrate, experimentally and in simulations, how astroid clocking of pinwheel ASI enables ferromagnetic domains to be gradually grown or reversed at will. Richer dynamics arise when the clock protocol allows both growth and reversal to occur simultaneously. With astroid clocking, complex spatio-temporal behaviors of magnetic metamaterials become easily controllable with high fidelity.
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Affiliation(s)
- Johannes H Jensen
- Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Anders Strømberg
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Ida Breivik
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, Norway
| | - Arthur Penty
- Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Miguel Angel Niño
- ALBA Synchrotron Light Facility, Carrer de la Llum 2 - 26, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Muhammad Waqas Khaliq
- ALBA Synchrotron Light Facility, Carrer de la Llum 2 - 26, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, Carrer de la Llum 2 - 26, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Gunnar Tufte
- Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Erik Folven
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, Norway
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2
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Hu W, Zhang Z, Liao Y, Li Q, Shi Y, Zhang H, Zhang X, Niu C, Wu Y, Yu W, Zhou X, Guo H, Wang W, Xiao J, Yin L, Liu Q, Shen J. Distinguishing artificial spin ice states using magnetoresistance effect for neuromorphic computing. Nat Commun 2023; 14:2562. [PMID: 37142614 PMCID: PMC10160026 DOI: 10.1038/s41467-023-38286-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 04/24/2023] [Indexed: 05/06/2023] Open
Abstract
Artificial spin ice (ASI) consisting patterned array of nano-magnets with frustrated dipolar interactions offers an excellent platform to study frustrated physics using direct imaging methods. Moreover, ASI often hosts a large number of nearly degenerated and non-volatile spin states that can be used for multi-bit data storage and neuromorphic computing. The realization of the device potential of ASI, however, critically relies on the capability of transport characterization of ASI, which has not been demonstrated so far. Using a tri-axial ASI system as the model system, we demonstrate that transport measurements can be used to distinguish the different spin states of the ASI system. Specifically, by fabricating a tri-layer structure consisting a permalloy base layer, a Cu spacer layer and the tri-axial ASI layer, we clearly resolve different spin states in the tri-axial ASI system using lateral transport measurements. We have further demonstrated that the tri-axial ASI system has all necessary required properties for reservoir computing, including rich spin configurations to store input signals, nonlinear response to input signals, and fading memory effect. The successful transport characterization of ASI opens up the prospect for novel device applications of ASI in multi-bit data storage and neuromorphic computing.
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Affiliation(s)
- Wenjie Hu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Zefeng Zhang
- Frontier Institute of Chip and System, Fudan University, Shanghai, China
- Research Institute of Intelligent Complex Systems and ISTBI, Fudan University, Shanghai, China
| | - Yanghui Liao
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Qiang Li
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Yang Shi
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Huanyu Zhang
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Xumeng Zhang
- Frontier Institute of Chip and System, Fudan University, Shanghai, China
| | - Chang Niu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Yu Wu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
| | - Weichao Yu
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Xiaodong Zhou
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Hangwen Guo
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Wenbin Wang
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - Jiang Xiao
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
- Shanghai Research Center for Quantum Sciences, Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China
| | - Lifeng Yin
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China.
- Shanghai Qi Zhi Institute, Shanghai, China.
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
- Shanghai Research Center for Quantum Sciences, Shanghai, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China.
- State Key Laboratory of Integrated Chips and Systems, Fudan University, Shanghai, China.
| | - Qi Liu
- Frontier Institute of Chip and System, Fudan University, Shanghai, China.
- State Key Laboratory of Integrated Chips and Systems, Fudan University, Shanghai, China.
| | - Jian Shen
- State Key Laboratory of Surface Physics, Institute for Nanoelectronic Devices and Quantum Computing, and Department of Physics, Fudan University, Shanghai, China.
- Shanghai Qi Zhi Institute, Shanghai, China.
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
- Shanghai Research Center for Quantum Sciences, Shanghai, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, China.
- Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, Shanghai, China.
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3
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Li F, Guan Y, Wang P, Wang Z, Fang C, Gu K, Parkin SSP. All-electrical reading and writing of spin chirality. SCIENCE ADVANCES 2022; 8:eadd6984. [PMID: 36516254 DOI: 10.1126/sciadv.add6984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Spintronics promises potential data encoding and computing technologies. Spin chirality plays a very important role in the properties of many topological and noncollinear magnetic materials. Here, we propose the all-electrical detection and manipulation of spin chirality in insulating chiral antiferromagnets. We demonstrate that the spin chirality in insulating epitaxial films of TbMnO3 can be read electrically via the spin Seebeck effect and can be switched by electric fields via the multiferroic coupling of the spin chirality to the ferroelectric polarization. Moreover, multivalued states of the spin chirality can be realized by the combined application of electric and magnetic fields. Our results are a path toward next-generation, low-energy consumption memory and logic devices that rely on spin chirality.
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Affiliation(s)
- Fan Li
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Yicheng Guan
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Peng Wang
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Zhong Wang
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Chi Fang
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Ke Gu
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Stuart S P Parkin
- NISE Department, Max Planck Institute of Microstructure Physics, Halle, Germany
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4
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Bingham NS, Zhang X, Ramberger J, Heinonen O, Leighton C, Schiffer P. Collective Ferromagnetism of Artificial Square Spin Ice. PHYSICAL REVIEW LETTERS 2022; 129:067201. [PMID: 36018663 DOI: 10.1103/physrevlett.129.067201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/04/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
We study the temperature and magnetic field dependence of the total magnetic moment of large-area permalloy artificial square spin ice arrays. The temperature dependence and hysteresis behavior are consistent with the coherent magnetization reversal expected in the Stoner-Wohlfarth model, with clear deviations due to interisland interactions at small lattice spacing. Through micromagnetic simulations, we explore this behavior and demonstrate that the deviations result from increasingly complex magnetization reversal at small lattice spacing, induced by interisland interactions, and depending critically on details of the island shapes. These results establish new means to tune the physical properties of artificial spin ice structures and other interacting nanomagnet systems, such as patterned magnetic media.
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Affiliation(s)
- N S Bingham
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - X Zhang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - J Ramberger
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - O Heinonen
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - P Schiffer
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
- Department of Physics, Yale University, New Haven, Connecticut 06511, USA
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5
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Puttock R, Andersen IM, Gatel C, Park B, Rosamond MC, Snoeck E, Kazakova O. Defect-induced monopole injection and manipulation in artificial spin ice. Nat Commun 2022; 13:3641. [PMID: 35752624 PMCID: PMC9233697 DOI: 10.1038/s41467-022-31309-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/13/2022] [Indexed: 11/17/2022] Open
Abstract
Lithographically defined arrays of nanomagnets are well placed for application in areas such as probabilistic computing or reconfigurable magnonics due to their emergent collective dynamics and writable magnetic order. Among them are artificial spin ice (ASI), which are arrays of binary in-plane macrospins exhibiting geometric frustration at the vertex interfaces. Macrospin flips in the arrays create topologically protected magnetic charges, or emergent monopoles, which are bound to an antimonopole to conserve charge. In the absence of controllable pinning, it is difficult to manipulate individual monopoles in the array without also influencing other monopole excitations or the counter-monopole charge. Here, we tailor the local magnetic order of a classic ASI lattice by introducing a ferromagnetic defect with shape anisotropy into the array. This creates monopole injection sites at nucleation fields below the critical lattice switching field. Once formed, the high energy monopoles are fixed to the defect site and may controllably propagate through the lattice under stimulation. Defect programing of bound monopoles within the array allows fine control of the pathways of inverted macrospins. Such control is a necessary prerequisite for the realization of functional devices, e. g. reconfigurable waveguide in nanomagnonic applications. Artificial spin ice systems offer a promising platform to study the motion of emergent magnetic monopoles, but controlled nucleation of monopoles is challenging. Here the authors demonstrate controlled injection and propagation of emergent monopoles in an artificial spin ice utilizing ferromagnetic defects.
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Affiliation(s)
- Robert Puttock
- Quantum Materials and Sensors, National Physical Laboratory, Teddington, UK.
| | - Ingrid M Andersen
- Centre d'Elaboration de Materiaux et d'Etudes Structurales, Toulouse, France
| | - Christophe Gatel
- Centre d'Elaboration de Materiaux et d'Etudes Structurales, Toulouse, France
| | - Bumsu Park
- Centre d'Elaboration de Materiaux et d'Etudes Structurales, Toulouse, France
| | - Mark C Rosamond
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK
| | - Etienne Snoeck
- Centre d'Elaboration de Materiaux et d'Etudes Structurales, Toulouse, France
| | - Olga Kazakova
- Quantum Materials and Sensors, National Physical Laboratory, Teddington, UK
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6
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Donnelly C, Hierro-Rodríguez A, Abert C, Witte K, Skoric L, Sanz-Hernández D, Finizio S, Meng F, McVitie S, Raabe J, Suess D, Cowburn R, Fernández-Pacheco A. Complex free-space magnetic field textures induced by three-dimensional magnetic nanostructures. NATURE NANOTECHNOLOGY 2022; 17:136-142. [PMID: 34931031 PMCID: PMC8850196 DOI: 10.1038/s41565-021-01027-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/07/2021] [Indexed: 05/23/2023]
Abstract
The design of complex, competing effects in magnetic systems-be it via the introduction of nonlinear interactions1-4, or the patterning of three-dimensional geometries5,6-is an emerging route to achieve new functionalities. In particular, through the design of three-dimensional geometries and curvature, intrastructure properties such as anisotropy and chirality, both geometry-induced and intrinsic, can be directly controlled, leading to a host of new physics and functionalities, such as three-dimensional chiral spin states7, ultrafast chiral domain wall dynamics8-10 and spin textures with new spin topologies7,11. Here, we advance beyond the control of intrastructure properties in three dimensions and tailor the magnetostatic coupling of neighbouring magnetic structures, an interstructure property that allows us to generate complex textures in the magnetic stray field. For this, we harness direct write nanofabrication techniques, creating intertwined nanomagnetic cobalt double helices, where curvature, torsion, chirality and magnetic coupling are jointly exploited. By reconstructing the three-dimensional vectorial magnetic state of the double helices with soft-X-ray magnetic laminography12,13, we identify the presence of a regular array of highly coupled locked domain wall pairs in neighbouring helices. Micromagnetic simulations reveal that the magnetization configuration leads to the formation of an array of complex textures in the magnetic induction, consisting of vortices in the magnetization and antivortices in free space, which together form an effective B field cross-tie wall14. The design and creation of complex three-dimensional magnetic field nanotextures opens new possibilities for smart materials15, unconventional computing2,16, particle trapping17,18 and magnetic imaging19.
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Affiliation(s)
- Claire Donnelly
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.
| | - Aurelio Hierro-Rodríguez
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain
- CINN (CSIC-Universidad de Oviedo), El Entrego, Spain
| | - Claas Abert
- University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, Vienna, Austria
| | - Katharina Witte
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
- Berlin Partner für Wirtschaft und Technologie GmbH, Berlin, Germany
| | - Luka Skoric
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | | | - Simone Finizio
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Fanfan Meng
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Stephen McVitie
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - Jörg Raabe
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Dieter Suess
- University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, Vienna, Austria
| | - Russell Cowburn
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
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7
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Zhang X, Duzgun A, Lao Y, Subzwari S, Bingham NS, Sklenar J, Saglam H, Ramberger J, Batley JT, Watts JD, Bromley D, Chopdekar RV, O'Brien L, Leighton C, Nisoli C, Schiffer P. String Phase in an Artificial Spin Ice. Nat Commun 2021; 12:6514. [PMID: 34764259 PMCID: PMC8585881 DOI: 10.1038/s41467-021-26734-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/19/2021] [Indexed: 11/11/2022] Open
Abstract
One-dimensional strings of local excitations are a fascinating feature of the physical behavior of strongly correlated topological quantum matter. Here we study strings of local excitations in a classical system of interacting nanomagnets, the Santa Fe Ice geometry of artificial spin ice. We measured the moment configuration of the nanomagnets, both after annealing near the ferromagnetic Curie point and in a thermally dynamic state. While the Santa Fe Ice lattice structure is complex, we demonstrate that its disordered magnetic state is naturally described within a framework of emergent strings. We show experimentally that the string length follows a simple Boltzmann distribution with an energy scale that is associated with the system’s magnetic interactions and is consistent with theoretical predictions. The results demonstrate that string descriptions and associated topological characteristics are not unique to quantum models but can also provide a simplifying description of complex classical systems with non-trivial frustration. Strings of local excitations are interesting features of a strongly correlated topological quantum matter. Here, the authors show that Boltzmann-distributed strings of local excitations also describe the topological physics of the Santa Fe geometry of artificial spin ice, which is a classical thermal system.
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Affiliation(s)
- Xiaoyu Zhang
- Department of Applied Physics, Yale University, New Haven, CT, 06511, USA.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Ayhan Duzgun
- Theoretical Division and Center for Nonlinear Studies, MS B258, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Yuyang Lao
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Shayaan Subzwari
- Department of Applied Physics, Yale University, New Haven, CT, 06511, USA
| | - Nicholas S Bingham
- Department of Applied Physics, Yale University, New Haven, CT, 06511, USA
| | - Joseph Sklenar
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Department of Physics and Astronomy, Wayne State University, Detroit, MI, 48201, USA
| | - Hilal Saglam
- Department of Applied Physics, Yale University, New Haven, CT, 06511, USA
| | - Justin Ramberger
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Joseph T Batley
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Justin D Watts
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA.,School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Daniel Bromley
- Department of Physics, University of Liverpool, Liverpool, L69 3BX, United Kingdom
| | - Rajesh V Chopdekar
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Liam O'Brien
- Department of Physics, University of Liverpool, Liverpool, L69 3BX, United Kingdom
| | - Chris Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Cristiano Nisoli
- Theoretical Division and Center for Nonlinear Studies, MS B258, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Peter Schiffer
- Department of Applied Physics, Yale University, New Haven, CT, 06511, USA. .,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. .,Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. .,Department of Physics, Yale University, New Haven, CT, 06511, USA.
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8
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Realization of macroscopic ratchet effect based on nonperiodic and uneven potentials. Sci Rep 2021; 11:16617. [PMID: 34400750 PMCID: PMC8368205 DOI: 10.1038/s41598-021-96192-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/04/2021] [Indexed: 11/28/2022] Open
Abstract
Ratchet devices allow turning an ac input signal into a dc output signal. A ratchet device is set by moving particles driven by zero averages forces on asymmetric potentials. Hybrid nanostructures combining artificially fabricated spin ice nanomagnet arrays with superconducting films have been identified as a good choice to develop ratchet nanodevices. In the current device, the asymmetric potentials are provided by charged Néel walls located in the vertices of spin ice magnetic honeycomb array, whereas the role of moving particles is played by superconducting vortices. We have experimentally obtained ratchet effect for different spin ice I configurations and for vortex lattice moving parallel or perpendicular to magnetic easy axes. Remarkably, the ratchet magnitudes are similar in all the experimental runs; i. e. different spin ice I configurations and in both relevant directions of the vortex lattice motion. We have simulated the interplay between vortex motion directions and a single asymmetric potential. It turns out vortices interact with uneven asymmetric potentials, since they move with trajectories crossing charged Néel walls with different orientations. Moreover, we have found out the asymmetric pair potentials which generate the local ratchet effect. In this rocking ratchet the particles (vortices) on the move are interacting each other (vortex lattice); therefore, the ratchet local effect turns into a global macroscopic effect. In summary, this ratchet device benefits from interacting particles moving in robust and topological protected type I spin ice landscapes.
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9
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Paterson GW, Macauley GM, Macêdo R. Field‐Driven Reversal Models in Artificial Spin Ice. ADVANCED THEORY AND SIMULATIONS 2021. [DOI: 10.1002/adts.202100109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gary W. Paterson
- SUPA, School of Physics and Astronomy University of Glasgow Glasgow G12 8QQ UK
- James Watt School of Engineering Electronics and Nanoscale Engineering Division University of Glasgow Glasgow G12 8QQ UK
| | - Gavin M. Macauley
- SUPA, School of Physics and Astronomy University of Glasgow Glasgow G12 8QQ UK
| | - Rair Macêdo
- James Watt School of Engineering Electronics and Nanoscale Engineering Division University of Glasgow Glasgow G12 8QQ UK
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10
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Saha S, Zhou J, Hofhuis K, Kákay A, Scagnoli V, Heyderman LJ, Gliga S. Spin-Wave Dynamics and Symmetry Breaking in an Artificial Spin Ice. NANO LETTERS 2021; 21:2382-2389. [PMID: 33689358 DOI: 10.1021/acs.nanolett.0c04294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Artificial spin ices are periodic arrangements of interacting nanomagnets which allow investigating emergent phenomena in the presence of geometric frustration. Recently, it has been shown that artificial spin ices can be used as building blocks for creating functional materials, such as magnonic crystals. We investigate the magnetization dynamics in a system exhibiting anisotropic magnetostatic interactions owing to locally broken structural inversion symmetry. We find a rich spin-wave spectrum and investigate its evolution in an external magnetic field. We determine the evolution of individual modes, from building blocks up to larger arrays, highlighting the role of symmetry breaking in defining the mode profiles. Moreover, we demonstrate that the mode spectra exhibit signatures of long-range interactions in the system. These results contribute to the understanding of magnetization dynamics in spin ices beyond the kagome and square ice geometries and are relevant for the realization of reconfigurable magnonic crystals based on spin ices.
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Affiliation(s)
- Susmita Saha
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
| | - Jingyuan Zhou
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Kevin Hofhuis
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Attila Kákay
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - Valerio Scagnoli
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Laura J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Sebastian Gliga
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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11
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Parakkat VM, Macauley GM, Stamps RL, Krishnan KM. Configurable Artificial Spin Ice with Site-Specific Local Magnetic Fields. PHYSICAL REVIEW LETTERS 2021; 126:017203. [PMID: 33480755 DOI: 10.1103/physrevlett.126.017203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
We demonstrate ground state tunability for a hybrid artificial spin ice composed of Fe nanomagnets which are subject to site-specific exchange-bias fields, applied in integer multiples of the lattice along one sublattice of the classic square artificial spin ice. By varying this period, three distinct magnetic textures are identified: a striped ferromagnetic phase; an antiferromagnetic phase attainable through an external field protocol alone; and an unconventional ground state with magnetically charged pairs embedded in an antiferromagnetic matrix. Monte Carlo simulations support the results of field protocols and demonstrate that the pinning tunes relaxation timescales and their critical behavior.
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Affiliation(s)
- Vineeth Mohanan Parakkat
- Department of Materials Science and Engineering, 323 Roberts Hall, University of Washington, Seattle, Washington 98195, USA
| | - Gavin M Macauley
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Robert L Stamps
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Kannan M Krishnan
- Department of Materials Science and Engineering, 323 Roberts Hall, University of Washington, Seattle, Washington 98195, USA
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12
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Lyu YY, Ma X, Xu J, Wang YL, Xiao ZL, Dong S, Janko B, Wang H, Divan R, Pearson JE, Wu P, Kwok WK. Reconfigurable Pinwheel Artificial-Spin-Ice and Superconductor Hybrid Device. NANO LETTERS 2020; 20:8933-8939. [PMID: 33252230 DOI: 10.1021/acs.nanolett.0c04093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ability to control the potential landscape in a medium of interacting particles could lead to intriguing collective behavior and innovative functionalities. Here, we utilize spatially reconfigurable magnetic potentials of a pinwheel artificial-spin-ice (ASI) structure to tailor the motion of superconducting vortices. The reconstituted chain structures of the magnetic charges in the pinwheel ASI and the strong interaction between magnetic charges and superconducting vortices allow significant modification of the transport properties of the underlying superconducting thin film, resulting in a reprogrammable resistance state that enables a reversible and switchable vortex Hall effect. Our results highlight an effective and simple method of using ASI as an in situ reconfigurable nanoscale energy landscape to design reprogrammable superconducting electronics, which could also be applied to the in situ control of properties and functionalities in other magnetic particle systems, such as magnetic skyrmions.
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Affiliation(s)
- Yang-Yang Lyu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Xiaoyu Ma
- Department of Physics, University of Notre Dame, Notre Dame 46556, Indiana United States
| | - Jing Xu
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Yong-Lei Wang
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
| | - Zhi-Li Xiao
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Physics, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Sining Dong
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
| | - Boldizsar Janko
- Department of Physics, University of Notre Dame, Notre Dame 46556, Indiana United States
| | - Huabing Wang
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
- Purple Mountain Laboratories, Nanjing 211111, China
| | - Ralu Divan
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - John E Pearson
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Peiheng Wu
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China
| | - Wai-Kwong Kwok
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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13
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Huang Q, Wu W, Ai K, Liu J. Highly Sensitive Polydiacetylene Ensembles for Biosensing and Bioimaging. Front Chem 2020; 8:565782. [PMID: 33282824 PMCID: PMC7691385 DOI: 10.3389/fchem.2020.565782] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/19/2020] [Indexed: 01/10/2023] Open
Abstract
Polydiacetylenes are prepared from amphiphilic diacetylenes first through self-assembly and then polymerization. Different from common supramolecular assemblies, polydiacetylenes have stable structure and very special optical properties such as absorption, fluorescence, and Raman. The hydrophilic head of PDAs is easy to be chemically modified with functional groups for detection and imaging applications. PDAs will undergo a specific color change from blue to red, fluorescence enhancement and Raman spectrum changes in the presence of receptor ligands. These properties allow PDA-based sensors to have high sensitivity and specificity during analysis. Therefore, the PDAs have been widely used for detection of viruses, bacteria, proteins, antibiotics, hormones, sialic acid, metal ions and as probes for bioimaging in recent years. In this review, the preparation, polymerization, and detection mechanisms of PDAs are discussed, and some representative research advances in the field of bio-detection and bioimaging are highlighted.
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Affiliation(s)
- Qiong Huang
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Wei Wu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China.,Department of Geriatric Surgery, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Kelong Ai
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China.,Hunan Provincial Key Laboratory of Cardiovascular Research, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, China
| | - Jianhua Liu
- Department of Radiology, The Second Hospital of Jilin University, Changchun, China
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14
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Lehmann J, Bortis A, Derlet PM, Donnelly C, Leo N, Heyderman LJ, Fiebig M. Relation between microscopic interactions and macroscopic properties in ferroics. NATURE NANOTECHNOLOGY 2020; 15:896-900. [PMID: 32958934 DOI: 10.1038/s41565-020-0763-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
The driving force in materials to spontaneously form states with magnetic or electric order is of fundamental importance for basic research and device technology. The macroscopic properties and functionalities of these ferroics depend on the size, distribution and morphology of domains; that is, of regions across which such uniform order is maintained1. Typically, extrinsic factors such as strain profiles, grain size or annealing procedures control the size and shape of the domains2-5, whereas intrinsic parameters are often difficult to extract due to the complexity of a processed material. Here, we achieve this separation by building artificial crystals of planar nanomagnets that are coupled by well-defined, tuneable and competing magnetic interactions6-9. Aside from analysing the domain configurations, we uncover fundamental intrinsic correlations between the microscopic interactions establishing magnetically compensated order and the macroscopic manifestations of these interactions in basic physical properties. Experiment and simulations reveal how competing interactions can be exploited to control ferroic hallmark properties such as the size and morphology of domains, topological properties of domain walls or their thermal mobility.
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Affiliation(s)
- Jannis Lehmann
- Laboratory for Multifunctional Ferroic Materials, Department of Materials, ETH Zurich, Zurich, Switzerland.
| | - Amadé Bortis
- Laboratory for Multifunctional Ferroic Materials, Department of Materials, ETH Zurich, Zurich, Switzerland.
| | - Peter M Derlet
- Condensed Matter Theory Group, Paul Scherrer Institute, Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Claire Donnelly
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, Villigen, Switzerland
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Naëmi Leo
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, Villigen, Switzerland
- Nanomagnetism Group, CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - Laura J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, Villigen, Switzerland
| | - Manfred Fiebig
- Laboratory for Multifunctional Ferroic Materials, Department of Materials, ETH Zurich, Zurich, Switzerland.
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15
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Lendinez S, Jungfleisch MB. Magnetization dynamics in artificial spin ice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:013001. [PMID: 31600143 DOI: 10.1088/1361-648x/ab3e78] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this topical review, we present key results of studies on magnetization dynamics in artificial spin ice (ASI), which are arrays of magnetically interacting nanostructures. Recent experimental and theoretical progress in this emerging area, which is at the boundary between research on frustrated magnetism and high-frequency studies of artificially created nanomagnets, is reviewed. The exploration of ASI structures has revealed fascinating discoveries in correlated spin systems. Artificially created spin ice lattices offer unique advantages as they allow for a control of the interactions between the elements by their geometric properties and arrangement. Magnonics, on the other hand, is a field that explores spin dynamics in the gigahertz frequency range in magnetic micro- and nanostructures. In this context, magnonic crystals are particularly important as they allow the modification of spin-wave properties and the observation of band gaps in the resonance spectra. Very recently, there has been considerable progress, experimentally and theoretically, in combining aspects of both fields-artificial spin ice and magnonics-enabling new functionalities in magnonic and spintronic applications using ASI, as well as providing a deeper understanding of geometrical frustration in the gigahertz range. Different approaches for the realization of ASI structures and their experimental characterization in the high-frequency range are described and the appropriate theoretical models and simulations are reviewed. Special attention is devoted to linking these findings to the quasi-static behavior of ASI and dynamic investigations in magnonics in an effort to bridge the gap between both areas further and to stimulate new research endeavors.
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Affiliation(s)
- S Lendinez
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States of America
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16
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Wyss M, Gliga S, Vasyukov D, Ceccarelli L, Romagnoli G, Cui J, Kleibert A, Stamps RL, Poggio M. Stray-Field Imaging of a Chiral Artificial Spin Ice during Magnetization Reversal. ACS NANO 2019; 13:13910-13916. [PMID: 31820931 DOI: 10.1021/acsnano.9b05428] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Artificial spin ices are a class of metamaterials consisting of magnetostatically coupled nanomagnets. Their interactions give rise to emergent behavior, which has the potential to be harnessed for the creation of functional materials. Consequently, the ability to map the stray field of such systems can be decisive for gaining an understanding of their properties. Here, we use a scanning nanometer-scale superconducting quantum interference device (SQUID) to image the magnetic stray field distribution of an artificial spin ice system exhibiting structural chirality as a function of applied magnetic fields at 4.2 K. The images reveal that the magnetostatic interaction gives rise to a measurable bending of the magnetization at the edges of the nanomagnets. Micromagnetic simulations predict that, owing to the structural chirality of the system, this edge bending is asymmetric in the presence of an external field and gives rise to a preferred direction for the reversal of the magnetization. This effect is not captured by models assuming a uniform magnetization. Our technique thus provides a promising means for understanding the collective response of artificial spin ices and their interactions.
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Affiliation(s)
- Marcus Wyss
- Department of Physics , University of Basel , 4056 Basel , Switzerland
| | - Sebastian Gliga
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow , G12 8QQ , United Kingdom
- Paul Scherrer Institute , Villigen 5232 , Switzerland
| | - Denis Vasyukov
- Department of Physics , University of Basel , 4056 Basel , Switzerland
| | | | - Giulio Romagnoli
- Department of Physics , University of Basel , 4056 Basel , Switzerland
| | - Jizhai Cui
- Paul Scherrer Institute , Villigen 5232 , Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zürich , 8093 Zürich , Switzerland
| | | | - Robert L Stamps
- Department of Physics and Astronomy , University of Manitoba , Winnipeg , R3T 2N2 , Canada
| | - Martino Poggio
- Department of Physics , University of Basel , 4056 Basel , Switzerland
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17
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Danelius E, Ohm RG, Ahsanullah, Mulumba M, Ong H, Chemtob S, Erdelyi M, Lubell WD. Dynamic Chirality in the Mechanism of Action of Allosteric CD36 Modulators of Macrophage-Driven Inflammation. J Med Chem 2019; 62:11071-11079. [DOI: 10.1021/acs.jmedchem.9b00918] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Emma Danelius
- Department of Pediatrics, Centre Hospitalier Universitaire (CHU) Sainte—Justine Research Center, Montréal H3T 1C5, Québec, Canada
| | | | | | | | | | - Sylvain Chemtob
- Department of Pediatrics, Centre Hospitalier Universitaire (CHU) Sainte—Justine Research Center, Montréal H3T 1C5, Québec, Canada
| | - Mate Erdelyi
- Department of Chemistry—BMC, Uppsala University, Husargatan 3, Uppsala SE-752 37, Sweden
- The Swedish NMR Centre, Medicinaregatan 5, Gothenburg SE-413 90, Sweden
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18
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Nanomagnetic encoding of shape-morphing micromachines. Nature 2019; 575:164-168. [DOI: 10.1038/s41586-019-1713-2] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 09/04/2019] [Indexed: 01/09/2023]
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19
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Rollano V, Muñoz-Noval A, Gomez A, Valdes-Bango F, Martin JI, Velez M, Osorio MR, Granados D, Gonzalez EM, Vicent JL. Topologically protected superconducting ratchet effect generated by spin-ice nanomagnets. NANOTECHNOLOGY 2019; 30:244003. [PMID: 30790770 DOI: 10.1088/1361-6528/ab0923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We have designed, fabricated and tested a robust superconducting ratchet device based on topologically frustrated spin ice nanomagnets. The device is made of a magnetic Co honeycomb array embedded in a superconducting Nb film. This device is based on three simple mechanisms: (i) the topology of the Co honeycomb array frustrates in-plane magnetic configurations in the array yielding a distribution of magnetic charges which can be ordered or disordered with in-plane magnetic fields, following spin ice rules; (ii) the local vertex magnetization, which consists of a magnetic half vortex with two charged magnetic Néel walls; (iii) the interaction between superconducting vortices and the asymmetric potentials provided by the Néel walls. The combination of these elements leads to a superconducting ratchet effect. Thus, superconducting vortices driven by alternating forces and moving on magnetic half vortices generate a unidirectional net vortex flow. This ratchet effect is independent of the distribution of magnetic charges in the array.
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Affiliation(s)
- V Rollano
- IMDEA-Nanociencia, Cantoblanco, E-28049 Madrid, Spain
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20
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Li Y, Paterson GW, Macauley GM, Nascimento FS, Ferguson C, Morley SA, Rosamond MC, Linfield EH, MacLaren DA, Macêdo R, Marrows CH, McVitie S, Stamps RL. Superferromagnetism and Domain-Wall Topologies in Artificial "Pinwheel" Spin Ice. ACS NANO 2019; 13:2213-2222. [PMID: 30588800 DOI: 10.1021/acsnano.8b08884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
For over ten years, arrays of interacting single-domain nanomagnets, referred to as artificial spin ices, have been engineered with the aim to study frustration in model spin systems. Here, we use Fresnel imaging to study the reversal process in "pinwheel" artificial spin ice, a modified square ASI structure obtained by rotating each island by some angle about its midpoint. Our results demonstrate that a simple 45° rotation changes the magnetic ordering from antiferromagnetic to ferromagnetic, creating a superferromagnet which exhibits mesoscopic domain growth mediated by domain wall nucleation and coherent domain propagation. We observe several domain-wall configurations, most of which are direct analogues to those seen in continuous ferromagnetic films. However, charged walls also appear due to the geometric constraints of the system. Changing the orientation of the external magnetic field allows control of the nature of the spin reversal with the emergence of either one- or two-dimensional avalanches. This property of pinwheel ASI could be employed to tune devices based on magnetotransport phenomena such as Hall circuits.
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Affiliation(s)
- Yue Li
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Gary W Paterson
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Gavin M Macauley
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Fabio S Nascimento
- Departamento de Física , Universidade Federal de Viçosa , Viçosa 36570-900 , Minas Gerais , Brazil
| | - Ciaran Ferguson
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Sophie A Morley
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
- Department of Physics , University of California , Santa Cruz , California 95064 , United States
| | - Mark C Rosamond
- School of Electronic and Electrical Engineering , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Edmund H Linfield
- School of Electronic and Electrical Engineering , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Donald A MacLaren
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Rair Macêdo
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Christopher H Marrows
- School of Physics and Astronomy , University of Leeds , Leeds LS2 9JT , United Kingdom
| | - Stephen McVitie
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
| | - Robert L Stamps
- SUPA, School of Physics and Astronomy , University of Glasgow , Glasgow G12 8QQ , United Kingdom
- Department of Physics and Astronomy , University of Manitoba , Manitoba R3T 2N2 , Canada
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21
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Mukhopadhyay AK, Xie T, Liebchen B, Schmelcher P. Dimensional coupling-induced current reversal in two-dimensional driven lattices. Phys Rev E 2018; 97:050202. [PMID: 29906956 DOI: 10.1103/physreve.97.050202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Indexed: 06/08/2023]
Abstract
We show that the direction of directed particle transport in a two-dimensional ac-driven lattice can be dynamically reversed by changing the structure of the lattice in the direction perpendicular to the applied driving force. These structural changes introduce dimensional coupling effects, the strength of which governs the timescale of the current reversals. The underlying mechanism is based on the fact that dimensional coupling allows the particles to explore regions of phase space which are inaccessible otherwise. The experimental realization for cold atoms in ac-driven optical lattices is discussed.
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Affiliation(s)
- Aritra K Mukhopadhyay
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Tianting Xie
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- College of Mathematics, Sichuan University, Chengdu 610065, China
| | - Benno Liebchen
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
- Institute for Theoretical Physics II: Soft Matter, Heinrich-Heine Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Peter Schmelcher
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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22
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Effect of FePd alloy composition on the dynamics of artificial spin ice. Sci Rep 2018; 8:4750. [PMID: 29556046 PMCID: PMC5859261 DOI: 10.1038/s41598-018-23208-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/27/2018] [Indexed: 11/18/2022] Open
Abstract
Artificial spin ices (ASI) are arrays of single domain nano-magnetic islands, arranged in geometries that give rise to frustrated magnetostatic interactions. It is possible to reach their ground state via thermal annealing. We have made square ASI using different FePd alloys to vary the magnetization via co-sputtering. From a polarized state the samples were incrementally heated and we measured the vertex population as a function of temperature using magnetic force microscopy. For the higher magnetization FePd sample, we report an onset of dynamics at T = 493 K, with a rapid collapse into >90% ground state vertices. In contrast, the low magnetization sample started to fluctuate at lower temperatures, T = 393 K and over a wider temperature range but only reached a maximum of 25% of ground state vertices. These results indicate that the interaction strength, dynamic temperature range and pathways can be finely tuned using a simple co-sputtering process. In addition we have compared our experimental values of the blocking temperature to those predicted using the simple Néel-Brown two-state model and find a large discrepancy which we attribute to activation volumes much smaller than the island volume.
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23
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Bramwell ST. Artificial spin ice: A ratchet made of tiny magnets. NATURE MATERIALS 2017; 16:1053-1054. [PMID: 29058726 DOI: 10.1038/nmat5004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Affiliation(s)
- Steven T Bramwell
- Department of Physics and Astronomy and at the London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AJ, UK
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