51
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Vergara LI, Cao J, Rogado N, Wang YQ, Chaudhury RP, Cava RJ, Lorenz B, Musfeldt JL. Magnetoelastic coupling in multiferroic Ni3V2O8. PHYSICAL REVIEW B 2009; 80:052303. [DOI: 10.1103/physrevb.80.052303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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52
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Abstract
The study of abrupt increases in magnetization with magnetic field known as metamagnetic transitions has opened a rich vein of new physics in itinerant electron systems, including the discovery of quantum critical end points with a marked propensity to develop new kinds of order. However, the electric analogue of the metamagnetic critical end point, a "metaelectric" critical end point, has been rarely studied. Multiferroic materials wherein magnetism and ferroelectricity are cross-coupled are ideal candidates for the exploration of this novel possibility using magnetic-field (H) as a tuning parameter. Herein, we report the discovery of a magnetic-field-induced metaelectric transition in multiferroic BiMn(2)O(5), in which the electric polarization (P) switches polarity along with a concomitant Mn spin-flop transition at a critical magnetic field H(c). The simultaneous metaelectric and spin-flop transitions become sharper upon cooling but remain a continuous cross-over even down to 0.5 K. Near the P = 0 line realized at mu(0)H(c) approximately 18 T below 20 K, the dielectric constant (epsilon) increases significantly over wide field and temperature (T) ranges. Furthermore, a characteristic power-law behavior is found in the P(H) and epsilon(H) curves at T = 0.66 K. These findings indicate that a magnetic-field-induced metaelectric critical end point is realized in BiMn(2)O(5) near zero temperature.
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53
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Martínez-Lope M, Retuerto M, García-Hernández M, Alonso J. Preparation, structural and magnetic characterization of DyCrMnO5. J SOLID STATE CHEM 2009. [DOI: 10.1016/j.jssc.2008.11.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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54
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Smirnov AI, Svistov LE, Prozorova LA, Zheludev A, Lumsden MD, Ressouche E, Petrenko OA, Nishikawa K, Kimura S, Hagiwara M, Kindo K, Shapiro AY, Demianets LN. Chiral and collinear ordering in a distorted triangular antiferromagnet. PHYSICAL REVIEW LETTERS 2009; 102:037202. [PMID: 19257385 DOI: 10.1103/physrevlett.102.037202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Indexed: 05/27/2023]
Abstract
Magnetization, specific heat, and neutron diffraction measurements are used to map out the entire magnetic phase diagram of KFe(MoO4)2. This stacked triangular antiferromagnet is structurally similar to the famous multiferroic system RbFe(MoO4)2. Because of an additional small crystallographic distortion, it contains two sets of inequivalent distorted magnetic triangular lattices. As a result, the spin network breaks down into two intercalated yet almost independent magnetic subsystems. One is a collinear antiferromagnet that shows a simple spin-flop behavior in applied magnetic fields. The other is a helimagnet that instead goes through a series of exotic commensurate-incommensurate phase transformations. In the various phases one observes either true three-dimensional or unconventional quasi-two-dimensional ordering.
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Affiliation(s)
- A I Smirnov
- P. L. Kapitza Institute for Physical Problems RAS, 119334 Moscow, Russia
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55
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Volkova LM, Marinin DV. Crystal chemistry aspects of the magnetically induced ferroelectricity in TbMn(2)O(5) and BiMn(2)O(5). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:015903. [PMID: 21817234 DOI: 10.1088/0953-8984/21/1/015903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The origin of magnetic frustration was stated and the ions, whose shift is accompanied by emerging magnetic ordering and ferroelectricity in TbMn(2)O(5) and BiMn(2)O(5), were determined on the basis of calculating the magnetic coupling parameters by using the structural data. The displacements accompanying the magnetic ordering are not polar, they just induce changes of bond valence (charge disordering) of Mn1 and Mn2, thus creating instability in the crystal structure. The approximation of the bond valence to the initial value (charge ordering) under magnetic ordering conditions is only possible again due to polar displacement of Mn2 (or O1) and O4 ions along the b axis which is the cause of the ferroelectric transition.
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Affiliation(s)
- L M Volkova
- Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 690022 Vladivostok, Russia
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56
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Ye F, Ren Y, Fernandez-Baca JA, Mook HA, Lynn JW, Chaudhury RP, Wang YQ, Lorenz B, Chu CW. Magnetic switching and phase competition in the multiferroic antiferromagnet Mn1−xFexWO4. PHYSICAL REVIEW B 2008; 78:193101. [DOI: 10.1103/physrevb.78.193101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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57
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58
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Radaelli PG, Chapon LC, Daoud-Aladine A, Vecchini C, Brown PJ, Chatterji T, Park S, Cheong SW. Electric field switching of antiferromagnetic domains in YMn2O5: a probe of the multiferroic mechanism. PHYSICAL REVIEW LETTERS 2008; 101:067205. [PMID: 18764498 DOI: 10.1103/physrevlett.101.067205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Indexed: 05/26/2023]
Abstract
We employ neutron spherical polarimetry to determine the nature and population of the coexisting antiferromagnetic domains in multiferroic YMn2O5. By applying an electric field, we prove that reversing the electrical polarization results in the population inversion of two types of in-plane domains, related to each other by inversion. Our results are completely consistent with the exchange-striction mechanism of ferroelectricity, and support a unified model where cycloidal ordering is induced by coupling to the main magnetic order parameter.
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Affiliation(s)
- P G Radaelli
- ISIS facility, Rutherford Appleton Laboratory-STFC, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom
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59
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Giovannetti G, van den Brink J. Electronic correlations decimate the ferroelectric polarization of multiferroic homn2o5. PHYSICAL REVIEW LETTERS 2008; 100:227603. [PMID: 18643459 DOI: 10.1103/physrevlett.100.227603] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Indexed: 05/26/2023]
Abstract
We show that electronic correlations decimate the intrinsic ferroelectric polarization of multiferroic manganites RMn2O5, where R is a rare earth element. Such is manifest from ab initio band structure computations that account for the Coulomb interactions between the manganese 3d electrons--the root of magnetism in RMn2O5. Including these leads to an amplitude and direction of polarization of HoMn2O5 that agree with experiment. The decimation is caused by a near cancellation of the ionic polarization induced by the lattice and the electronic one due to valence charge redistributions.
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Affiliation(s)
- Gianluca Giovannetti
- Institute Lorentz for Theoretical Physics, Leiden University, P.O. Box 9506, 2300 RA Leiden, The Netherlands
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60
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Harris AB, Aharony A, Entin-Wohlman O. Order parameters and phase diagram of multiferroic RMn2O5. PHYSICAL REVIEW LETTERS 2008; 100:217202. [PMID: 18518630 DOI: 10.1103/physrevlett.100.217202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Indexed: 05/26/2023]
Abstract
The generic magnetic phase diagram of multiferroic RMn2O5 (with R=Y, Ho, Tb, Er, Tm), which allows different sequences of ordered magnetic structures for different R's and different control parameters, is described using order parameters which explicitly incorporate the magnetic symmetry. A phenomenological magnetoelectric coupling is used to explain why some of these magnetic phases are also ferroelectric. Several new experiments, which can test this theory, are proposed.
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Affiliation(s)
- A B Harris
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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61
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Hu J. Microscopic origin of magnetoelectric coupling in noncollinear multiferroics. PHYSICAL REVIEW LETTERS 2008; 100:077202. [PMID: 18352590 DOI: 10.1103/physrevlett.100.077202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Indexed: 05/26/2023]
Abstract
An universal microscopic mechanism to understand the interplay between the electric and magnetic degrees of freedom in noncollinear multiferroics is developed. In a system with a strong spin-orbit coupling, we show that there is a pure electric mechanism that the ferroelectricity is generated by noncollinear magnetism through an electric current cancellation process, which saves the pure electric energy. This mechanism provides a simple estimation and sets a physical limitation of the value of ferroelectricity in noncollinear multiferroic materials.
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Affiliation(s)
- Jiangping Hu
- Department of Physics, Purdue University, West Lafayette, Indiana 47007, USA
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62
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Detlefs C, Duc F, Kazeĭ ZA, Vanacken J, Frings P, Bras W, Lorenzo JE, Canfield PC, Rikken GLJA. Direct Observation of the High Magnetic Field Effect on the Jahn-Teller State in TbVO4. PHYSICAL REVIEW LETTERS 2008; 100:056405. [PMID: 18352402 DOI: 10.1103/physrevlett.100.056405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Indexed: 05/26/2023]
Abstract
We report the first direct observation of the influence of high magnetic fields on the Jahn-Teller (JT) transition in TbVO(4). Contrary to spectroscopic and magnetic methods, x-ray diffraction directly measures the JT distortion; the splitting between the (311)/(131) and (202)/(022) pairs of Bragg reflections is proportional to the order parameter. Our experimental results are compared to mean-field calculations, taking into account all possible orientations of the grains relative to the applied field, and qualitative agreement is obtained.
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Affiliation(s)
- C Detlefs
- European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France
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63
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Bodenthin Y, Staub U, García-Fernández M, Janoschek M, Schlappa J, Golovenchits EI, Sanina VA, Lushnikov SG. Manipulating the magnetic structure with electric fields in multiferroic ErMn2O5. PHYSICAL REVIEW LETTERS 2008; 100:027201. [PMID: 18232913 DOI: 10.1103/physrevlett.100.027201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Indexed: 05/25/2023]
Abstract
Based on measurements of soft x-ray magnetic diffraction under in situ applied electric field, we report on significant manipulation and exciting of commensurate magnetic order in multiferroic ErMn2O5. The induced magnetic scattering intensity arises at the commensurate magnetic Bragg position whereas the initial magnetic signal almost persists. We demonstrate the possibility to imprint a magnetic response function in ErMn2O5 by applying an electric field.
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Affiliation(s)
- Y Bodenthin
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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64
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Koo J, Song C, Ji S, Lee JS, Park J, Jang TH, Yang CH, Park JH, Jeong YH, Lee KB, Koo TY, Park YJ, Kim JY, Wermeille D, Goldman AI, Srajer G, Park S, Cheong SW. Non-resonant and resonant x-ray scattering studies on multiferroic TbMn2O5. PHYSICAL REVIEW LETTERS 2007; 99:197601. [PMID: 18233114 DOI: 10.1103/physrevlett.99.197601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2007] [Indexed: 05/25/2023]
Abstract
Comprehensive x-ray scattering studies, including resonant scattering at Mn L, Tb L, and M edges, were performed on single crystals of TbMn2O5 for crystallographic data to elucidate the nature of its commensurate and incommensurate phases. The scattering results provide direct evidence of symmetry lowering to the ferroelectric phase driven by magnetically induced lattice modulations and show the presence of multiple magnetic orders. The competing orders under spin-frustrated geometry are believed to cause discommensuration and result in the commensurate-to-incommensurate phase transition around 24 K. It is proposed that the low temperature incommensurate phase consists of commensurate domains separated by antiphase domain walls which change both signs of spontaneous polarizations and x-ray scattering amplitudes for forbidden reflections.
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Affiliation(s)
- J Koo
- eSSC and Department of Physics, POSTECH, Pohang, Korea
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65
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Prokhnenko O, Feyerherm R, Mostovoy M, Aliouane N, Dudzik E, Wolter AUB, Maljuk A, Argyriou DN. Coupling of frustrated ising spins to the magnetic cycloid in multiferroic TbMnO(3). PHYSICAL REVIEW LETTERS 2007; 99:177206. [PMID: 17995366 DOI: 10.1103/physrevlett.99.177206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Indexed: 05/25/2023]
Abstract
We report on diffraction measurements on multiferroic TbMnO(3) which demonstrate that the Tb- and Mn-magnetic orders are coupled below the ferroelectric transition T(FE) = 28 K. For T<T(FE) the magnetic propagation vectors (tau) for Tb and Mn are locked so that tau(Tb) = tau(Mn), while below T(N)(Tb) = 7 K we find that tau(Tb) and tau(Mn) lock-in to rational values of 3/7b* and 2/7b*, respectively, and obey the relation 3tau(Tb)-tau(Mn)=1. We explain this novel matching of wave vectors within the frustrated anisotropic next-nearest-neighbor Ising model coupled to a periodic external field produced by the Mn-spin order. The tau(Tb)=tau(Mn) behavior is recovered when Tb magnetization is small, while the tau(Tb) = 3/7 regime is stabilized at low temperatures by a peculiar arrangement of domain walls in the ordered state of Ising-like Tb spins.
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Affiliation(s)
- O Prokhnenko
- Hahn-Meitner-Institute, Glienicker Str. 100, D-14109 Berlin, Germany
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66
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Wang C, Guo GC, He L. Ferroelectricity driven by the noncentrosymmetric magnetic ordering in multiferroic TbMn(2)O(5): a first-principles study. PHYSICAL REVIEW LETTERS 2007; 99:177202. [PMID: 17995362 DOI: 10.1103/physrevlett.99.177202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Indexed: 05/25/2023]
Abstract
The ground state structural, electronic, and magnetic properties of multiferroic TbMn(2)O(5) are investigated via first-principles calculations. We show that the ferroelectricity in TbMn(2)O(5) is driven by the noncentrosymmetric magnetic ordering, without invoking the spin-orbit coupling and noncollinear spins. The intrinsic electric polarization in this compound is calculated to be 1187 nC cm(-2), an order of magnitude larger than previously thought.
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Affiliation(s)
- Chenjie Wang
- Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, 230026, People's Republic of China
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67
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Nénert G, Palstra TTM. Prediction for new magnetoelectric fluorides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2007; 19:406213. [PMID: 22049112 DOI: 10.1088/0953-8984/19/40/406213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We use symmetry considerations in order to predict new magnetoelectric fluorides. In addition to these magnetoelectric properties, we discuss which among these fluorides are the ones susceptible to present multiferroic properties. We emphasize that several materials exhibit ferromagnetic properties. This ferromagnetism should enhance the interplay between the magnetic and dielectric properties in these materials.
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68
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Muñoz A, Alonso JA, Martínez‐Lope MJ, Martínez JL. Synthesis and Study of the Crystallographic and Magnetic Structure of HoFeMnO
5. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200601144] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Angel Muñoz
- Dpto. de Física Aplicada, EPS, Universidad Carlos III, Avda. Universidad 30, 28911, Leganés‐Madrid, Spain
| | - José A. Alonso
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049, Cantoblanco‐Madrid, Spain
| | | | - José L. Martínez
- Instituto de Ciencia de Materiales de Madrid, CSIC, 28049, Cantoblanco‐Madrid, Spain
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69
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Okamoto J, Huang DJ, Mou CY, Chao KS, Lin HJ, Park S, Cheong SW, Chen CT. Symmetry of multiferroicity in a frustrated magnet TbMn2O5. PHYSICAL REVIEW LETTERS 2007; 98:157202. [PMID: 17501376 DOI: 10.1103/physrevlett.98.157202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Indexed: 05/15/2023]
Abstract
Based on measurements of soft-x-ray magnetic scattering and symmetry considerations, we demonstrate that the magnetoelectric effect in TbMn2O5 arises from an internal field determined by S-->q--> x S-->-q--> with S-->q--> being the magnetization at modulation vector q-->, whereas the magnetoelastic effect in the exchange energy governs the response to external electric fields. Our results set fundamental symmetry constraints on the microscopic mechanism of multiferroicity in frustrated magnets.
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Affiliation(s)
- J Okamoto
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
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70
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Katsura H, Balatsky AV, Nagaosa N. Dynamical magnetoelectric coupling in helical magnets. PHYSICAL REVIEW LETTERS 2007; 98:027203. [PMID: 17358643 DOI: 10.1103/physrevlett.98.027203] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Indexed: 05/14/2023]
Abstract
We develop a theory of collective mode dynamics in the helical magnets coupled to electric polarization via spin-orbit interaction. The low-lying modes associated with the ferroelectricity are not the transverse optical phonons, but are the spin waves hybridized with the electric polarization. This hybridization leads to the Drude-like dielectric function epsilon(omega) in the limit of zero magnetic anisotropy. There are two additional low-lying modes: phason of the spiral and rotation of helical plane along the polarization axis. Role of these low-lying modes in the neutron scattering and antiferromagnetic resonance is revealed, and a novel experiment to detect the dynamical magnetoelectric coupling is discussed.
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Affiliation(s)
- Hosho Katsura
- Department of Applied Physics, the University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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71
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Cheong SW, Mostovoy M. Multiferroics: a magnetic twist for ferroelectricity. NATURE MATERIALS 2007; 6:13-20. [PMID: 17199121 DOI: 10.1038/nmat1804] [Citation(s) in RCA: 959] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Magnetism and ferroelectricity are essential to many forms of current technology, and the quest for multiferroic materials, where these two phenomena are intimately coupled, is of great technological and fundamental importance. Ferroelectricity and magnetism tend to be mutually exclusive and interact weakly with each other when they coexist. The exciting new development is the discovery that even a weak magnetoelectric interaction can lead to spectacular cross-coupling effects when it induces electric polarization in a magnetically ordered state. Such magnetic ferroelectricity, showing an unprecedented sensitivity to ap plied magnetic fields, occurs in 'frustrated magnets' with competing interactions between spins and complex magnetic orders. We summarize key experimental findings and the current theoretical understanding of these phenomena, which have great potential for tuneable multifunctional devices.
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Affiliation(s)
- Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics & Astronomy, 136 Frelinghuysen Road, Piscataway 08854, New Jersey, USA
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72
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Sergienko IA, Sen C, Dagotto E. Ferroelectricity in the magnetic E-phase of orthorhombic perovskites. PHYSICAL REVIEW LETTERS 2006; 97:227204. [PMID: 17155837 DOI: 10.1103/physrevlett.97.227204] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Indexed: 05/12/2023]
Abstract
We show that the symmetry of the spin zigzag chain E phase of the orthorhombic perovskite manganites and nickelates allows for the existence of a finite ferroelectric polarization. The proposed microscopic mechanism is independent of spin-orbit coupling. We predict that the polarization induced by the E-type magnetic order can potentially be enhanced by up to 2 orders of magnitude with respect to that in the spiral magnetic phases of TbMnO3 and similar multiferroic compounds.
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Affiliation(s)
- Ivan A Sergienko
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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73
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Tanaka S, Katsura H, Nagaosa N. Electron localization or delocalization in incommensurate helical magnets. PHYSICAL REVIEW LETTERS 2006; 97:116404. [PMID: 17025912 DOI: 10.1103/physrevlett.97.116404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Indexed: 05/12/2023]
Abstract
The electronic states in incommensurate helical magnets are studied theoretically from the viewpoint of the localization or delocalization. It is found that in the multiband system with a relativistic spin-orbit interaction, the electronic wave functions show both an extended and localized nature along the helical axis depending on the orbital, helical wave number, and the direction of the plane on which spins rotate. The possible realization of this localization is discussed.
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Affiliation(s)
- Shu Tanaka
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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74
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Taniguchi K, Abe N, Takenobu T, Iwasa Y, Arima T. Ferroelectric polarization flop in a frustrated magnet MnWO4 induced by a magnetic field. PHYSICAL REVIEW LETTERS 2006; 97:097203. [PMID: 17026396 DOI: 10.1103/physrevlett.97.097203] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Indexed: 05/12/2023]
Abstract
The relationship between magnetic order and ferroelectric properties has been investigated for MnWO4 with a long-wavelength magnetic structure. Spontaneous electric polarization is observed in an elliptical spiral spin phase. The magnetic-field dependence of electric polarization indicates that the noncollinear spin configuration plays a key role for the appearance of the ferroelectric phase. An electric polarization flop from the b direction to the a direction has been observed when a magnetic field above 10 T is applied along the b axis. This result demonstrates that an electric polarization flop can be induced by a magnetic field in a simple system without rare-earth 4f moments.
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Affiliation(s)
- K Taniguchi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
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75
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Combined powder neutron and X-ray diffraction study of charge and orbital order in Bi0.75Sr0.25MnO3. J SOLID STATE CHEM 2006. [DOI: 10.1016/j.jssc.2006.01.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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76
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Chapon LC, Radaelli PG, Blake GR, Park S, Cheong SW. Ferroelectricity induced by acentric spin-density waves in YMn2O5. PHYSICAL REVIEW LETTERS 2006; 96:097601. [PMID: 16606315 DOI: 10.1103/physrevlett.96.097601] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Indexed: 05/08/2023]
Abstract
The commensurate and incommensurate magnetic structures of the magnetoelectric system YMn2O5, as determined from neutron diffraction, were found to be spin-density waves lacking a global center of symmetry. We propose a model, based on a simple magnetoelastic coupling to the lattice, which enables us to predict the polarization based entirely on the observed magnetic structure. Our data accurately reproduce the temperature dependence of the spontaneous polarization, particularly its sign reversal at the commensurate-incommensurate transition.
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Affiliation(s)
- L C Chapon
- ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX, United Kingdom
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77
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Mostovoy M. Ferroelectricity in spiral magnets. PHYSICAL REVIEW LETTERS 2006; 96:067601. [PMID: 16606047 DOI: 10.1103/physrevlett.96.067601] [Citation(s) in RCA: 306] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Indexed: 05/08/2023]
Abstract
It was recently observed that the ferroelectrics showing the strongest sensitivity to an applied magnetic field are spiral magnets. We present a phenomenological theory of inhomogeneous ferroelectric magnets, which describes their thermodynamics and magnetic field behavior, e.g., dielectric susceptibility anomalies at magnetic transitions and sudden flops of electric polarization in an applied magnetic field. We show that electric polarization can also be induced at domain walls and that magnetic vortices carry electric charge.
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Affiliation(s)
- Maxim Mostovoy
- Materials Science Center, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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78
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Lawes G, Harris AB, Kimura T, Rogado N, Cava RJ, Aharony A, Entin-Wohlman O, Yildirim T, Kenzelmann M, Broholm C, Ramirez AP. Magnetically driven ferroelectric order in Ni3V2O8. PHYSICAL REVIEW LETTERS 2005; 95:087205. [PMID: 16196898 DOI: 10.1103/physrevlett.95.087205] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Indexed: 05/04/2023]
Abstract
We show that long-range ferroelectric and incommensurate magnetic order appear simultaneously in a single phase transition in Ni3V2O8. The temperature and magnetic-field dependence of the spontaneous polarization show a strong coupling between magnetic and ferroelectric orders. We determine the magnetic symmetry using Landau theory for continuous phase transitions, which shows that the spin structure alone can break spatial inversion symmetry leading to ferroelectric order. This phenomenological theory explains our experimental observation that the spontaneous polarization is restricted to lie along the crystal b axis and predicts that the magnitude should be proportional to a magnetic order parameter.
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Affiliation(s)
- G Lawes
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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