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Ma C, Lin Y, Yang H, Tian H, Shi L, Zeng J, Li J. Direct Observation of Magnetic-Ion Off-Centering-Induced Ferroelectricity in Multiferroic Manganite Pr(Sr0.1Ca0.9)2 Mn2O7. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:6328-6332. [PMID: 26390084 DOI: 10.1002/adma.201502385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/27/2015] [Indexed: 06/05/2023]
Abstract
Ferroelectricity in multiferroic Pr(Sr0.1 Ca0.9)2 Mn2 O7 is found to originate from the off-centering of Mn ions. This polar displacement is energetically stabilized by the cooperative interplay of lattice deformation induced by orbital ordering and oxygen octahedral tilting. This mechanism implies that magnetism and ferroelectricity arise from the same magnetic ions, providing direct evidence for the magnetic-ion off-centering-driven ferroelectricity.
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Affiliation(s)
- Chao Ma
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Yue Lin
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Huaixin Yang
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Huanfang Tian
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Lei Shi
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Jie Zeng
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China
| | - Jianqi Li
- Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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Radaelli PG, Dhesi SS. The contribution of Diamond Light Source to the study of strongly correlated electron systems and complex magnetic structures. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2013.0148. [PMID: 25624510 DOI: 10.1098/rsta.2013.0148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We review some of the significant contributions to the field of strongly correlated materials and complex magnets, arising from experiments performed at the Diamond Light Source (Harwell Science and Innovation Campus, Didcot, UK) during the first few years of operation (2007-2014). We provide a comprehensive overview of Diamond research on topological insulators, multiferroics, complex oxides and magnetic nanostructures. Several experiments on ultrafast dynamics, magnetic imaging, photoemission electron microscopy, soft X-ray holography and resonant magnetic hard and soft X-ray scattering are described.
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Affiliation(s)
- P G Radaelli
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - S S Dhesi
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
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Winkler EL, Tovar M, Causa MT. Delocalized and localized states of eg electrons in half-doped manganites. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:296003. [PMID: 23807798 DOI: 10.1088/0953-8984/25/29/296003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have studied the magnetic behaviour of half-doped manganite Y0.5Ca0.5MnO3 in an extended range of temperatures by means of magnetic susceptibility, χ(T), and electron spin resonance (ESR) experiments. At high temperature the system crystallizes in an orthorhombic structure. The resistivity value, ρ ≃ 0.05 Ω cm at 500 K, indicates a metallic behaviour, while the Curie-Weiss dependence of χ(T) and the thermal evolution of the ESR parameters are very well described by a model that considers a system conformed by localized Mn(4+) cores, [Formula: see text], and itinerant, eg, electrons. The strong coupling between t2g and eg electrons results in an enhanced Curie constant and an FM Curie-Weiss temperature that overcomes the AFM interactions between the [Formula: see text] cores. A transition to a more distorted phase is observed at T ≈ 500 K and signatures of localization of the eg electrons appear in the χ(T) behaviour below 300 K. A new Curie-Weiss regime is observed, where the Curie-constant value is consistent with dimer formation. Based on mean-field calculations, the dimer formation is predicted as a function of the interaction strength between the t2g and eg electrons.
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Affiliation(s)
- E L Winkler
- Centro Atómico Bariloche, 8400 S C de Bariloche, RN, Argentina.
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Fink J, Schierle E, Weschke E, Geck J. Resonant elastic soft x-ray scattering. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:056502. [PMID: 23563216 DOI: 10.1088/0034-4885/76/5/056502] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Resonant (elastic) soft x-ray scattering (RSXS) offers a unique element, site and valence specific probe to study spatial modulations of charge, spin and orbital degrees of freedom in solids on the nanoscopic length scale. It is not only used to investigate single-crystalline materials. This method also enables one to examine electronic ordering phenomena in thin films and to zoom into electronic properties emerging at buried interfaces in artificial heterostructures. During the last 20 years, this technique, which combines x-ray scattering with x-ray absorption spectroscopy, has developed into a powerful probe to study electronic ordering phenomena in complex materials and furthermore delivers important information on the electronic structure of condensed matter. This review provides an introduction to the technique, covers the progress in experimental equipment, and gives a survey on recent RSXS studies of ordering in correlated electron systems and at interfaces.
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Affiliation(s)
- J Fink
- Leibniz-Institute for Solid State and Materials Research Dresden, PO Box 270116, D-01171 Dresden, Germany.
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Johnstone GE, Perring TG, Sikora O, Prabhakaran D, Boothroyd AT. Ground state in a half-doped manganite distinguished by neutron spectroscopy. PHYSICAL REVIEW LETTERS 2012; 109:237202. [PMID: 23368255 DOI: 10.1103/physrevlett.109.237202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 09/05/2012] [Indexed: 06/01/2023]
Abstract
We have measured the spin-wave spectrum of the half-doped bilayer manganite Pr(Ca,Sr)(2)Mn(2)O(7) in its spin, charge, and orbital ordered phase. The measurements, which extend throughout the Brillouin zone and cover the entire one-magnon spectrum, are compared critically with spin-wave calculations for different models of the electronic ground state. The data are described very well by the Goodenough model, which has weakly interacting ferromagnetic zig-zag chains in the CE-type arrangement. A model that allows ferromagnetic dimers to form within the zigzags is inconsistent with the data. The analysis conclusively rules out the strongly bound dimer (Zener polaron) model.
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Affiliation(s)
- G E Johnstone
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford, OX1 3PU, United Kingdom
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Lovesey SW, Knight KS, Detlefs C, Huang SW, Scagnoli V, Staub U. Acentric magnetic and optical properties of chalcopyrite (CuFeS2). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:216001. [PMID: 22534165 DOI: 10.1088/0953-8984/24/21/216001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The absence of spatial inversion symmetry at both local (point group 4) and global (crystal class (4)2m) levels greatly influences the electronic properties of chalcopyrite (CuFeS(2)). The predicted dichroic signals (natural circular, non-reciprocal and magneto-chiral) and resonant, parity-odd Bragg diffraction patterns at space-group forbidden reflections portray the uncommon, acentric symmetry. Despite extensive experimental investigations over several decades, by mineralogists, chemists and physicists, there is no consensus view about the electrical and magnetic properties of chalcopyrite. New spectroscopic and diffraction data, gathered at various temperatures in the vicinity of the copper and iron L(2,3) edges, provide necessary confidence in the magnetic motif used in our analytic simulations of x-ray scattering. With the sample held at 10 and 65 K, our data establish beyond reasonable doubt that there is no valence transition, and ordering of the copper moments as the origin of the low-temperature phase (T(c) ≈ 53 K) is ruled out.
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Bodenthin Y, Staub U, Piamonteze C, García-Fernández M, Martínez-Lope MJ, Alonso JA. Magnetic and electronic properties of RNiO₃ (R = Pr, Nd, Eu, Ho and Y) perovskites studied by resonant soft x-ray magnetic powder diffraction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:036002. [PMID: 21406873 DOI: 10.1088/0953-8984/23/3/036002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Soft x-ray resonant magnetic powder diffraction of the ([Formula: see text]) reflection at the Ni L(2, 3) edges is used to study the magnetic and electronic properties of a series of RNiO(3) materials (with R = Pr, Nd, Eu, Ho and Y) below the metal-insulator transition. The polarization and energy dependence of the reflection gives further support for a non-collinear magnetic structure and charge disproportionation in the whole RNiO(3) series. Only small changes in the spectra of the magnetic ([Formula: see text]) reflection and in the absorption spectra could be detected. The results are discussed with comparison to charge transfer multiplet calculations. Our results emphasize that the lighter and heavier RNiO(3) compounds are very similar from the point of view of their local electronic and magnetic state despite the strong change of the metal-to-insulator transition temperature.
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Affiliation(s)
- Y Bodenthin
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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