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Xu X, Huang FT, Cheong SW. Magnetic toroidicity. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:203002. [PMID: 38290166 DOI: 10.1088/1361-648x/ad2426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 01/30/2024] [Indexed: 02/01/2024]
Abstract
Directional non-reciprocity refers to the phenomenon where the motion in one direction differs from the motion in the opposite direction. This behavior is observed across various systems, such as one-way traffic and materials displaying electronic/optical directional dichroism, characterized by the symmetry of velocity vectors. Magnetic toroidal moments (MTMs), which typically arise from rotational spin arrangements, also possess the symmetry of velocity vectors, making them inherently directionally non-reciprocal. In this paper, we examine magnetic point groups (MPGs) that exhibit MTMs, subsequently leading to off-diagonal linear magnetoelectricity. Our focus is on the induction of MTMs through electric fields, magnetic fields, or shear stress, while enumerating the relevant MPGs. The findings of our study will serve as valuable guidance for future investigations on directional non-reciprocity, MTMs, and off-diagonal linear magnetoelectric effects.
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Affiliation(s)
- Xianghan Xu
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
| | - Fei-Ting Huang
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
| | - Sang-Wook Cheong
- Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, United States of America
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2
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Kimura K, Kimura T. Nonvolatile Switching of Large Nonreciprocal Optical Absorption at Shortwave Infrared Wavelengths. PHYSICAL REVIEW LETTERS 2024; 132:036901. [PMID: 38307053 DOI: 10.1103/physrevlett.132.036901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 10/07/2023] [Accepted: 12/06/2023] [Indexed: 02/04/2024]
Abstract
We report large nonreciprocal optical absorption at shortwave infrared (SWIR) wavelengths in the magnetoelectric (ME) antiferromagnet (AFM) LiNiPO_{4}. The difference in absorption coefficients for light propagating in opposite directions, divided by the sum, reaches up to ∼40% at 1450 nm. Moreover, the nonreciprocity is switched by a magnetic field in a nonvolatile manner. Using symmetry considerations, we reveal that the large nonreciprocal absorption is attributed to Ni^{2+} d-d transitions through the spin-orbit coupling. Furthermore, we propose that an even larger nonreciprocity can be achieved for a Ni-based ME AFM where electric dipoles of every NiO_{6} unit and Ni^{2+} spins are orthogonal and, respectively, form a collinear arrangement. This study provides a pathway toward nonvolatile switchable one-way transparency of SWIR light.
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Affiliation(s)
- Kenta Kimura
- Department of Materials Science, Osaka Metropolitan University, Osaka 599-8531, Japan
| | - Tsuyoshi Kimura
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
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Liang W, Zeng J, Qiao Z, Gao Y, Niu Q. Berry-Curvature Engineering for Nonreciprocal Directional Dichroism in Two-Dimensional Antiferromagnets. PHYSICAL REVIEW LETTERS 2023; 131:256901. [PMID: 38181334 DOI: 10.1103/physrevlett.131.256901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/02/2023] [Accepted: 11/17/2023] [Indexed: 01/07/2024]
Abstract
In two-dimensional antiferromagnets, we find that the mixed Berry curvature can be attributed as the geometrical origin of the nonreciprocal directional dichroism (NDD), which refers to the difference in light absorption between opposite propagation directions. This Berry curvature is closely related to the uniaxial strain in accordance with the symmetry constraint, leading to a highly tunable NDD, whose sign and strength can be tuned via strain direction. We choose the lattice model of MnBi_{2}Te_{4} as a concrete example. The coupling between mixed Berry curvature and strain also suggests the magnetic quadrupole of the Bloch wave packet as the macroscopic order parameter probed by the NDD in two dimensions, which is distinct from the multiferroic order P×M or the spin toroidal and quadrupole order within a unit cell in previous studies. Our work paves the way for the Berry-curvature engineering for optical nonreciprocity in two-dimensional antiferromagnets.
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Affiliation(s)
- Wenhao Liang
- International Centre for Quantum Design of Functional Materials, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Junjie Zeng
- Institute for Structure and Function, Department of Physics, and Chongqing Key Laboratory for Strongly Coupled Physics, Chongqing University, Chongqing 400044, China
| | - Zhenhua Qiao
- International Centre for Quantum Design of Functional Materials, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Yang Gao
- International Centre for Quantum Design of Functional Materials, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Qian Niu
- International Centre for Quantum Design of Functional Materials, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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4
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Sawada Y, Kimura S, Watanabe K, Yamaguchi Y, Arima T, Kimura T. Nonreciprocal Directional Dichroism in Magnetoelectric Spin Glass. PHYSICAL REVIEW LETTERS 2022; 129:217201. [PMID: 36461975 DOI: 10.1103/physrevlett.129.217201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/29/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
Optical absorption spectra in the visible and near-infrared light were measured for magnetoelectric spin glass Ni_{0.4}Mn_{0.6}TiO_{3} under various field-cooled conditions. Despite the absence of long-range magnetic-dipole order, this spin-glass system exhibits nonreciprocal directional dichroism (NDD) at zero external field after a magnetoelectric field-cooled procedure. This result is distinct from previous studies on NDD in systems with magnetic toroidal moments induced either by long-range magnetic-dipole order or by applying crossed electric and magnetic fields. The present Letter conclusively demonstrates that the observed NDD originates from magnetoelectrically induced ferroic order of magnetic toroidal moments without conventional magnetic-dipole order.
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Affiliation(s)
- Y Sawada
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - S Kimura
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - K Watanabe
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Y Yamaguchi
- Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan
| | - T Arima
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - T Kimura
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
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5
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Mohan S. Ambiguity in indexing electron diffraction patterns of R
3 crystals. ACTA CRYSTALLOGRAPHICA SECTION A FOUNDATIONS AND ADVANCES 2022; 78:507-514. [DOI: 10.1107/s2053273322008907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/06/2022] [Indexed: 11/15/2022]
Abstract
The R
3 space group inherently lacks 2110, m
001 and m_{{\bar 1}10} symmetry operations. However, in crystals with R
3 symmetry, these transformations produce `pseudoplanes' with the same interplanar spacing and angles as the original crystallographic planes, causing a lack of uniqueness in the electron diffraction (ED) pattern. The difference in atomic arrangements of pseudoplanes and original planes is reflected in the intensities of diffraction spots; it is hard to differentiate in standard ED patterns, frequently causing wrong assignment of the zone axes. The implications of this ambiguity in analysis of crystal orientations are discussed in detail and a suitable routine to follow while indexing R
3 ED patterns is proposed.
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Kurosawa H, Tomita S, Sawada K, Nakanishi T, Ueda T. Unity-order magnetochiral effects exhibited by a single metamolecule. OPTICS EXPRESS 2022; 30:37066-37075. [PMID: 36258624 DOI: 10.1364/oe.469675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
A numerical study predicts that a single metamolecule with magnetism and chirality has giant magnetochiral (MCh) effects at microwave frequencies. The magnetism is provided by the ferromagnetic resonance of ferrite under dc bias magnetic fields, while the chirality is provided by the spiral arrangement of dielectric cubes with Mie resonance. The dielectric and magnetic resonances interfere in the metamolecule, resulting in a two-order of magnitude enhancement of the MCh effect compared with that reported in previous studies. This prediction is verified experimentally. A unity-order directional difference in the refractive index caused by the MCh effect is also demonstrated. This study is a significant milestone in the practical use of the MCh effect.
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Visualizing rotation and reversal of the Néel vector through antiferromagnetic trichroism. Nat Commun 2022; 13:697. [PMID: 35121748 PMCID: PMC8816959 DOI: 10.1038/s41467-022-28215-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 01/10/2022] [Indexed: 11/10/2022] Open
Abstract
Conventional magnetic memories rely on bistable magnetic states, such as the up and down magnetization states in ferromagnets. Increasing the number of stable magnetic states in each cell, preferably composed of antiferromagnets without stray fields, promises to achieve higher-capacity memories. Thus far, such multi-stable antiferromagnetic states have been extensively studied in conducting systems. Here, we report on a striking optical response in the magnetoelectric collinear antiferromagnet Bi2CuO4, which is an insulating version of the representative spintronic material, CuMnAs, with four stable Néel vector orientations. We find that, due to a magnetoelectric effect in a visible range, which is enhanced by a peculiar local environment of Cu ions, absorption coefficient takes three discrete values depending on an angle between the propagation vector of light and the Néel vector—a phenomenon that we term antiferromagnetic trichroism. Furthermore, using this antiferromagnetic trichroism, we successfully visualize field-driven reversal and rotation of the Néel vector. Antiferromagnets have great promise for use in spin-based electronics; however, detecting the Neel vector is challenging due to the lack of a net magnetization. Here, Kimura et al demonstrate an intriguing optical response, where the optical absorption depends on the angle of the Neel vector.
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Vít J, Viirok J, Peedu L, Rõõm T, Nagel U, Kocsis V, Tokunaga Y, Taguchi Y, Tokura Y, Kézsmárki I, Balla P, Penc K, Romhányi J, Bordács S. In Situ Electric-Field Control of THz Nonreciprocal Directional Dichroism in the Multiferroic Ba_{2}CoGe_{2}O_{7}. PHYSICAL REVIEW LETTERS 2021; 127:157201. [PMID: 34678006 DOI: 10.1103/physrevlett.127.157201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
Nonreciprocal directional dichroism, also called the optical-diode effect, is an appealing functional property inherent to the large class of noncentrosymmetric magnets. However, the in situ electric control of this phenomenon is challenging as it requires a set of conditions to be fulfilled: Special symmetries of the magnetic ground state, spin excitations with comparable magnetic- and electric-dipole activity, and switchable electric polarization. We demonstrate the isothermal electric switch between domains of Ba_{2}CoGe_{2}O_{7} possessing opposite magnetoelectric susceptibilities. Combining THz spectroscopy and multiboson spin-wave analysis, we show that unbalancing the population of antiferromagnetic domains generates the nonreciprocal light absorption of spin excitations.
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Affiliation(s)
- J Vít
- Department of Physics, Budapest University of Technology and Economics, 1111 Budapest, Hungary
- Institute of Physics ASCR, Na Slovance 2, 182 21 Prague 8, Czech Republic
- Faculty of Nuclear Science and Physical Engineering, Czech Technical University, Břehová 7, 115 19 Prague 1, Czech Republic
| | - J Viirok
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - L Peedu
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - T Rõõm
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - U Nagel
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia
| | - V Kocsis
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Y Tokunaga
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Y Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Y Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics and Tokyo College, University of Tokyo, Tokyo 113-8656, Japan
| | - I Kézsmárki
- Department of Physics, Budapest University of Technology and Economics, 1111 Budapest, Hungary
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Balla
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box. 49, H-1525 Budapest, Hungary
| | - K Penc
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box. 49, H-1525 Budapest, Hungary
| | - J Romhányi
- Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, California 92697, USA
| | - S Bordács
- Department of Physics, Budapest University of Technology and Economics, 1111 Budapest, Hungary
- Hungarian Academy of Sciences, Premium Postdoctor Program, 1051 Budapest, Hungary
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Atzori M, Train C, Hillard EA, Avarvari N, Rikken GLJA. Magneto-chiral anisotropy: From fundamentals to perspectives. Chirality 2021; 33:844-857. [PMID: 34541710 DOI: 10.1002/chir.23361] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 11/08/2022]
Abstract
The interplay between chirality and magnetic fields gives rise to a cross effect referred to as magneto-chiral anisotropy (MChA), which can manifest itself in different physical properties of chiral magnetized materials. The first experimental demonstration of MChA was by optical means with visible light. Further optical manifestations of MChA have been evidenced across most of the electromagnetic spectrum, from terahertz to X-rays. Moreover, exploiting the versatility of molecular chemistry toward chiral magnetic systems, many efforts have been made to identify the microscopic origins of optical MChA, necessary to advance the effect toward technological applications. In parallel, the replacement of light by electric current has allowed the observation of nonreciprocal electrical charge transport in both molecular and inorganic conductors as a result of electrical MChA (eMChA). MChA in other domains such as sound propagation, photochemistry, and electrochemistry are still in their infancy, with only a few experimental demonstrations, and offer wide perspectives for further studies with potentially large impact, like the understanding of the homochirality of life. After a general introduction to MChA, we give a complete review of all these phenomena, particularly during the last decade.
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Affiliation(s)
- Matteo Atzori
- Laboratoire National des Champs Magnétiques Intenses (LNCMI), Univ. Grenoble Alpes, INSA Toulouse, Univ. Paul Sabatier, EMFL, CNRS, Toulouse, France
| | - Cyrille Train
- Laboratoire National des Champs Magnétiques Intenses (LNCMI), Univ. Grenoble Alpes, INSA Toulouse, Univ. Paul Sabatier, EMFL, CNRS, Toulouse, France
| | - Elizabeth A Hillard
- Institute de Chimie de la Matière Condensée de Bordeaux, CNRS, Univ. Bordeaux, Bordeaux INP, ICMCB, UMR 5026, Pessac, France
| | - Narcis Avarvari
- MOLTECH-Anjou, SFR MATRIX, Univ Angers, CNRS, Angers, France
| | - Geert L J A Rikken
- Laboratoire National des Champs Magnétiques Intenses (LNCMI), Univ. Grenoble Alpes, INSA Toulouse, Univ. Paul Sabatier, EMFL, CNRS, Toulouse, France
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Hayashida T, Kimura K, Urushihara D, Asaka T, Kimura T. Observation of Ferrochiral Transition Induced by an Antiferroaxial Ordering of Antipolar Structural Units in Ba(TiO)Cu 4(PO 4) 4. J Am Chem Soc 2021; 143:3638-3646. [PMID: 33630570 DOI: 10.1021/jacs.1c00391] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ferrochiral transition, i.e., a transition involving an emergence of chirality, provides an unique opportunity to achieve a nonvolatile reversible control of chirality with external fields. However, materials showing pure ferrochiral transitions, which are accompanied by no other types of ferroic transition, are exceedingly rare. In this study, we propose that a pure ferrochiral transition is achieved by a combination of antipolar and antiferroaxial orderings of structural units, and substantiate this proposal through a study of the chiral compound Ba(TiO)Cu4(PO4)4. Single crystal X-ray diffraction measurements have revealed that this material undergoes a second order ferrochiral transition whose order parameter is described by an antiferroaxial (staggered) rotation of antipolar structural units, thus demonstrating our proposal. Furthermore, by measuring spatial distributions of optical rotation, we successfully visualized a temperature evolution of ferrochiral domains across the transition temperature and demonstrated the relationship between chirality and optical rotation. This work provides a guide to find a pure ferrochiral transition, thus providing an opportunity to achieve a ferroic control of chirality.
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Affiliation(s)
- Takeshi Hayashida
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - Kenta Kimura
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - Daisuke Urushihara
- Division of Advanced Ceramics, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Toru Asaka
- Division of Advanced Ceramics and Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan
| | - Tsuyoshi Kimura
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
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Kimura S, Matsumoto M, Tanaka H. Electrical Switching of the Nonreciprocal Directional Microwave Response in a Triplon Bose-Einstein Condensate. PHYSICAL REVIEW LETTERS 2020; 124:217401. [PMID: 32530678 DOI: 10.1103/physrevlett.124.217401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/09/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
We present a microwave electron spin resonance study of the quantum spin dimer system TlCuCl_{3}, which shows the magnetic-field-induced ordering with both antiferromagnetic spin order and ferroelectricity by the Bose-Einstein condensation (BEC) of triplon quasiparticles. Our main achievement is an electrical switching of the nonreciprocal directional microwave response in the triplon BEC phase. High-speed directional control of microwave absorption by applying an electric field has been accomplished in this Letter. The strength of the observed nonreciprocal microwave response well agrees with the calculation based on Kubo theory with the parameters, evaluated from the static electric polarization in this material.
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Affiliation(s)
- Shojiro Kimura
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
| | | | - Hidekazu Tanaka
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan
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