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Cheng S, Li X, Xu C, Liu Y, Beleggia M, Wu L, Wang W, Petrovic C, Bellaiche L, Tao J, Zhu Y. Coexistence and Coupling of Multiple Charge Orderings and Spin States in Hexagonal Ferrite. NANO LETTERS 2021; 21:5782-5787. [PMID: 34170143 DOI: 10.1021/acs.nanolett.1c01624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The coupling between charge and spin orderings in strongly correlated systems plays a crucial role in fundamental physics and device applications. As a candidate of multiferroic materials, LuFe2O4 with a nominal Fe2.5+ valence state has the potential for strong charge-spin interactions; however, these interactions have not been fully understood until now. Here, combining complementary characterization methods with theoretical calculations, two types of charge orderings with distinct magnetic properties are revealed. The ground states of LuFe2O4 are decided by the parallel/antiparallel coupling of both charge and spin orderings in the adjacent FeO double layers. Whereas the ferroelectric charge ordering remains ferrimagnetic below 230 K, the antiferroelectric ordering undergoes antiferromagnetic-ferrimagnetic-paramagnetic transitions from 2 K to room temperature. This study demonstrates the unique aspects of strong spin-charge coupling within LuFe2O4. Our results shed light on the coexistence and competing nature of orderings in quantum materials.
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Affiliation(s)
- Shaobo Cheng
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Xing Li
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
- Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China
| | - Changsong Xu
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Yu Liu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Marco Beleggia
- DTU Nanolab, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Lijun Wu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wenbin Wang
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
| | - Cedomir Petrovic
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Jing Tao
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Yimei Zhu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States
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Nagase T, So YG, Yasui H, Ishida T, Yoshida HK, Tanaka Y, Saitoh K, Ikarashi N, Kawaguchi Y, Kuwahara M, Nagao M. Observation of domain wall bimerons in chiral magnets. Nat Commun 2021; 12:3490. [PMID: 34108478 PMCID: PMC8190141 DOI: 10.1038/s41467-021-23845-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/19/2021] [Indexed: 12/03/2022] Open
Abstract
Topological defects embedded in or combined with domain walls have been proposed in various systems, some of which are referred to as domain wall skyrmions or domain wall bimerons. However, the experimental observation of such topological defects remains an ongoing challenge. Here, using Lorentz transmission electron microscopy, we report the experimental discovery of domain wall bimerons in chiral magnet Co-Zn-Mn(110) thin films. By applying a magnetic field, multidomain structures develop, and simultaneously, chained or isolated bimerons arise as the localized state between the domains with the opposite in-plane components of net magnetization. The multidomain formation is attributed to magnetic anisotropy and dipolar interaction, and domain wall bimerons are stabilized by the Dzyaloshinskii-Moriya interaction. In addition, micromagnetic simulations show that domain wall bimerons appear for a wide range of conditions in chiral magnets with cubic magnetic anisotropy. Our results promote further study in various fields of physics.
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Affiliation(s)
- Tomoki Nagase
- Department of Electronics, Graduate School of Engineering, Nagoya University, Nagoya, Japan.
| | - Yeong-Gi So
- Department of Materials Science, Graduate School of Engineering Science, Akita University, Akita, Japan
| | - Hayata Yasui
- Department of Materials Science, Graduate School of Engineering Science, Akita University, Akita, Japan
| | - Takafumi Ishida
- Advanced Measurement Technology Center, Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, Japan
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Hiroyuki K Yoshida
- Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Yukio Tanaka
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Koh Saitoh
- Advanced Measurement Technology Center, Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, Japan
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Nobuyuki Ikarashi
- Department of Electronics, Graduate School of Engineering, Nagoya University, Nagoya, Japan
- Center for Integrated Research of Future Electronics, Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, Japan
| | - Yuki Kawaguchi
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Makoto Kuwahara
- Advanced Measurement Technology Center, Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, Japan.
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya, Japan.
| | - Masahiro Nagao
- Department of Electronics, Graduate School of Engineering, Nagoya University, Nagoya, Japan.
- Center for Integrated Research of Future Electronics, Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, Japan.
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Pozzi G, Rosi P, Tavabi AH, Karimi E, Dunin-Borkowski RE, Grillo V. A sorter for electrons based on magnetic elements. Ultramicroscopy 2021; 231:113287. [PMID: 33926773 DOI: 10.1016/j.ultramic.2021.113287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 04/01/2021] [Accepted: 04/10/2021] [Indexed: 10/21/2022]
Abstract
The orbital angular momentum (OAM) sorter is an electron optical device for the measurement of an electron's OAM. It is based on two phase elements, which are referred to as an "unwrapper" and a "corrector" and are located in Fourier conjugate planes. The simplest implementation of the sorter is based on electrostatic phase elements, such as a charged needle for the unwrapper and electrodes with alternating charges or potentials for the corrector. Here, we use a formal analogy between phase shifts introduced by charges and vertical currents to propose alternative designs for the sorter elements, which are based on phase shifts introduced by magnetic fields. We use this concept to provide a general guide for phase element design, which promises to provide improved reliability of phase control in electron optics.
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Affiliation(s)
- Giulio Pozzi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Department of Physics and Astronomy, University of Bologna, viale B. Pichat 6/2, 40127 Bologna, Italy
| | - Paolo Rosi
- Department FIM, University of Modena and Reggio Emilia, via G. Campi 213/a, 41125 Modena, Italy
| | - Amir H Tavabi
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Ebrahim Karimi
- Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Vincenzo Grillo
- Department FIM, University of Modena and Reggio Emilia, via G. Campi 213/a, 41125 Modena, Italy; CNR-Institute of Nanoscience-S3, via G. Campi 213/a, 41125 Modena, Italy.
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Magnetic antiskyrmions above room temperature in tetragonal Heusler materials. Nature 2017; 548:561-566. [DOI: 10.1038/nature23466] [Citation(s) in RCA: 400] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 06/21/2017] [Indexed: 12/25/2022]
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Somodi P, Twitchett-Harrison A, Midgley P, Kardynał B, Barnes C, Dunin-Borkowski R. Finite element simulations of electrostatic dopant potentials in thin semiconductor specimens for electron holography. Ultramicroscopy 2013; 134:160-6. [DOI: 10.1016/j.ultramic.2013.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/29/2013] [Accepted: 06/29/2013] [Indexed: 11/28/2022]
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Beleggia M, Pozzi G. Phase contrast image simulations for electron holography of magnetic and electric fields. Microscopy (Oxf) 2013; 62 Suppl 1:S43-54. [PMID: 23536699 DOI: 10.1093/jmicro/dft008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The research on flux line lattices and pancake vortices in superconducting materials, carried out within a long and fruitful collaboration with Akira Tonomura and his group at the Hitachi Advanced Research Laboratory, led us to develop a mathematical framework, based on the reciprocal representation of the magnetic vector potential, that enables us to simulate realistic phase images of fluxons. The aim of this paper is to review the main ideas underpinning our computational framework and the results we have obtained throughout the collaboration. Furthermore, we outline how to generalize the approach to model other samples and structures of interest, in particular thin ferromagnetic films, ferromagnetic nanoparticles and p-n junctions.
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Affiliation(s)
- Marco Beleggia
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs, Lyngby, Denmark.
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Fazzini P, Ortolani L, Pozzi G, Ubaldi F. Interference electron microscopy of one-dimensional electron-optical phase objects. Ultramicroscopy 2006. [DOI: 10.1016/j.ultramic.2006.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Fazzini PF, Pozzi G, Beleggia M. Electron optical phase-shifts by Fourier methods: Analytical versus numerical calculations. Ultramicroscopy 2005; 104:193-205. [PMID: 15899551 DOI: 10.1016/j.ultramic.2005.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Revised: 03/14/2005] [Accepted: 04/01/2005] [Indexed: 10/25/2022]
Abstract
The theoretical framework for the computation of electromagnetic fields and electron optical phase-shifts in Fourier space has been recently applied to objects with long-range fringing fields, such as reverse-biased p-n junctions and magnetic stripe domains near a specimen edge. In addition to new analytical results, in this work, we present a critical comparison between numerical and analytical computations. The influence of explicit and implicit boundary conditions on the phase shifts and phase-contrast images is also investigated in detail.
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Affiliation(s)
- P F Fazzini
- Department of Physics and Istituto Nazionale per la Fisica della Materia, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna, Italy.
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