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Khan S, Aw ESY, Nagle-Cocco LAV, Sud A, Ghosh S, Subhan MKB, Xue Z, Freeman C, Sagkovits D, Gutiérrez-Llorente A, Verzhbitskiy I, Arroo DM, Zollitsch CW, Eda G, Santos EJG, Dutton SE, Bramwell ST, Howard CA, Kurebayashi H. Spin-Glass States Generated in a van der Waals Magnet by Alkali-Ion Intercalation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2400270. [PMID: 39036829 DOI: 10.1002/adma.202400270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 06/18/2024] [Indexed: 07/23/2024]
Abstract
Tuning magnetic properties in layered van der Waals (vdW) materials has captured significant attention due to the efficient control of ground states by heterostructuring and external stimuli. Electron doping by electrostatic gating, interfacial charge transfer, and intercalation is particularly effective in manipulating the exchange and spin-orbit properties, resulting in a control of Curie temperature (TC) and magnetic anisotropy. Here, an uncharted role of intercalation is discovered to generate magnetic frustration. As a model study, Na atoms are intercalated into the vdW gaps of pristine Cr2Ge2Te6 (CGT) where generated magnetic frustration leads to emerging spin-glass states coexisting with a ferromagnetic order. A series of dynamic magnetic susceptibility measurements/analysis confirms the formation of magnetic clusters representing slow dynamics with a distribution of relaxation times. The intercalation also modifies other macroscopic physical parameters including the significant enhancement of TC from 66 to 240 K and the switching of magnetic easy-hard axis direction. This study identifies intercalation as a unique route to generate emerging frustrated spin states in simple vdW crystals.
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Affiliation(s)
- Safe Khan
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Eva S Y Aw
- Department of Physics & Astronomy, University College London, London, WC1H 0AH, UK
| | | | - Aakanksha Sud
- RIEC, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-0812, Japan
- FRIS, Tohoku University, 6-3, Aramaki, Aoba-Ku, Sendai, 980-0845, Japan
| | - Sukanya Ghosh
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, UK
| | - Mohammed K B Subhan
- Department of Physics & Astronomy, University College London, London, WC1H 0AH, UK
| | - Zekun Xue
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Charlie Freeman
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Dimitrios Sagkovits
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Araceli Gutiérrez-Llorente
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
- Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Madrid, 28933, Spain
| | - Ivan Verzhbitskiy
- Physics Department, National University of Singapore, Singapore 117551, Singapore
| | - Daan M Arroo
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | | | - Goki Eda
- Physics Department, National University of Singapore, Singapore 117551, Singapore
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117542, Singapore
| | - Elton J G Santos
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, UK
- Higgs Centre for Theoretical Physics, The University of Edinburgh, Edinburgh, EH9 3FD, UK
- Donostia International Physics Center, Donostia-San Sebastián, 20018, Spain
| | - Sian E Dutton
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Steven T Bramwell
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Chris A Howard
- Department of Physics & Astronomy, University College London, London, WC1H 0AH, UK
| | - Hidekazu Kurebayashi
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
- WPI-AIMR, Tohoku University, 2-1-1, Katahira, Sendai, 980-8577, Japan
- Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE, UK
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Setty C, Baggioli M, Zaccone A. Anharmonic theory of superconductivity and its applications to emerging quantum materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:173002. [PMID: 38252997 DOI: 10.1088/1361-648x/ad2159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
The role of anharmonicity on superconductivity has often been disregarded in the past. Recently, it has been recognized that anharmonic decoherence could play a fundamental role in determining the superconducting properties (electron-phonon coupling, critical temperature, etc) of a large class of materials, including systems close to structural soft-mode instabilities, amorphous solids and metals under extreme high-pressure conditions. Here, we review recent theoretical progress on the role of anharmonic effects, and in particular certain universal properties of anharmonic damping, on superconductivity. Our focus regards the combination of microscopic-agnostic effective theories for bosonic mediators with the well-established BCS theory and Migdal-Eliashberg theory for superconductivity. We discuss in detail the theoretical frameworks, their possible implementation within first-principles methods, and the experimental probes for anharmonic decoherence. Finally, we present several concrete applications to emerging quantum materials, including hydrides, ferroelectrics and systems with charge density wave instabilities.
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Affiliation(s)
- Chandan Setty
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, United States of America
| | - Matteo Baggioli
- Wilczek Quantum Center, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, People's Republic of China
| | - Alessio Zaccone
- Department of Physics 'A. Pontremoli', University of Milan, via Celoria 16, 20133 Milan, Italy
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB30HE Cambridge, United Kingdom
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3
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Kim S, Chen X, Fitzhugh W, Li X. Apical Charge Flux-Modulated In-Plane Transport Properties of Cuprate Superconductors. PHYSICAL REVIEW LETTERS 2018; 121:157001. [PMID: 30362810 DOI: 10.1103/physrevlett.121.157001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/25/2018] [Indexed: 06/08/2023]
Abstract
For copper-based superconductors, the maximum superconducting transition temperature T_{c,max} of different families measured from experiment can vary from 38 K in La_{2}CuO_{4} to 135 K in HgBa_{2}Ca_{2}Cu_{3}O_{8} at the optimal hole doping concentration. We demonstrate herein, using ab initio computations, a new trend suggesting that the cuprates with stronger out-of-CuO_{2}-plane chemical bonding between the apical anion (O, Cl) and apical cation (e.g., La, Hg, Bi, Tl) are generally correlated with higher T_{c,max} in experiments. We then show the underlying fundamental phenomena of coupled apical charge flux and lattice dynamics when the apical oxygen oscillates vertically. This triggers the charge flux among the apical cation, apical anion, and the in-plane CuO_{4} unit. The effect not only dynamically modulates the site energy of the hole at a given Cu site to control the in-plane charge transfer energy, but also can modulate the in-plane hole hopping integral simultaneously in a dynamic way by the cooperative apical charge fluxes.
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Affiliation(s)
- Sooran Kim
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Xi Chen
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - William Fitzhugh
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Xin Li
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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4
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Lee D, Seo J. Magnetic frustration of graphite oxide. Sci Rep 2017; 7:44690. [PMID: 28327606 PMCID: PMC5361081 DOI: 10.1038/srep44690] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 02/13/2017] [Indexed: 11/24/2022] Open
Abstract
Delocalized π electrons in aromatic ring structures generally induce diamagnetism. In graphite oxide, however, π electrons develop ferromagnetism due to the unique structure of the material. The π electrons are only mobile in the graphitic regions of graphite oxide, which are dispersed and surrounded by sp3-hybridized carbon atoms. The spin-glass behavior of graphite oxide is corroborated by the frequency dependence of its AC susceptibility. The magnetic susceptibility data exhibit a negative Curie temperature, field irreversibility, and slow relaxation. The overall results indicate that magnetic moments in graphite oxide slowly interact and develop magnetic frustration.
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Affiliation(s)
- Dongwook Lee
- Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.,Physics and Applied Physics, School of Physical &Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Jiwon Seo
- Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.,Department of Physics and Applied Physics, Yonsei University, Seoul, 120-749, Korea
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Viskadourakis Z, Sunku SS, Mukherjee S, Andersen BM, Ito T, Sasagawa T, Panagopoulos C. Ferroelectricity in underdoped La-based cuprates. Sci Rep 2015; 5:15268. [PMID: 26486276 PMCID: PMC4614081 DOI: 10.1038/srep15268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 09/03/2015] [Indexed: 12/02/2022] Open
Abstract
Doping a “parent” antiferromagnetic Mott insulator in cuprates leads to short-range electronic correlations and eventually to high-Tc superconductivity. However, the nature of charge correlations in the lightly doped cuprates remains unclear. Understanding the intermediate electronic phase in the phase diagram (between the parent insulator and the high-Tc superconductor) is expected to elucidate the complexity both inside and outside the superconducting dome, and in particular in the underdoped region. One such phase is ferroelectricity whose origin and relation to the properties of high-Tc superconductors is subject of current research. Here we demonstrate that ferroelectricity and the associated magnetoelectric coupling are in fact common in La-214 cuprates namely, La2-xSrxCuO4, La2LixCu1-xO4 and La2CuO4+x. It is proposed that ferroelectricity may result from local CuO6 octahedral distortions, associated with the dopant atoms and clustering of the doped charge carriers, which break spatial inversion symmetry at the local scale whereas magnetoelectric coupling can be tuned through Dzyaloshinskii-Moriya interaction.
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Affiliation(s)
- Z Viskadourakis
- Crete Center for Quantum Complexity and Nanotechnology, University of Crete, Heraklion 71003, Greece.,IESL-FORTH, Vassilika Vouton, Heraklion 71110, Greece
| | - S S Sunku
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - S Mukherjee
- Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - T Ito
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - C Panagopoulos
- Crete Center for Quantum Complexity and Nanotechnology, University of Crete, Heraklion 71003, Greece.,Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore.,Department of Physics, University of Crete, Heraklion 71003, Greece
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Mydosh JA. Spin glasses: redux: an updated experimental/materials survey. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:052501. [PMID: 25872613 DOI: 10.1088/0034-4885/78/5/052501] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This article reviews the 40+ year old spin-glass field and one of its earliest model interpretations as a spin density wave. Our description is from an experimental phenomenological point of view with emphasis on new spin glass materials and their relation to topical problems and strongly correlated materials in condensed matter physics. We first simply define a spin glass (SG), give its basic ingredients and explain how the spin glasses enter into the statistical mechanics of classical phase transitions. We then consider the four basic experimental properties to solidly characterize canonical spin glass behavior and introduce the early theories and models. Here the spin density wave (SDW) concept is used to explain the difference between a short-range SDW, i.e. a SG and, in contrast, a long-range SDW, i.e. a conventional magnetic phase transition. We continue with the present state of SG, its massive computer simulations and recent proposals of chiral glasses and quantum SG. We then collect and mention the various SG 'spin-off's'. A major section uncovers the fashionable unconventional materials that display SG-like freezing and glassy ground states, such as (high temperature) superconductors, heavy fermions, intermetallics and Heuslers, pyrochlor and spinels, oxides and chalogenides and exotics, e.g. quasicrystals. Some conclusions and future directions complete the review.
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Affiliation(s)
- J A Mydosh
- Kamerlingh Onnes Laboratory and Institute Lorentz, Leiden University, PO Box 9504, 2300RA Leiden, The Netherlands
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7
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Bao JK, Feng CM, Luo YK, Jiang H, Sun YL, Jiao WH, Shen CY, Xu ZA, Cao GH. Variable range hopping conductivity and spin glass behavior in spin-ladder Ba0.6K0.4Fe2Se3 single crystals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:026002. [PMID: 24316559 DOI: 10.1088/0953-8984/26/2/026002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Ba0.6K0.4Fe2Se3 (BKFS) single crystals were investigated by means of measurements of powder x-ray diffraction, temperature-dependent resistivity, anisotropic dc magnetization, ac magnetic susceptibility and specific heat. The powder x-ray diffraction indicates staggered iron displacements along the ladders with short and long Fe-Fe bond lengths (2.64(2) and 2.91(2) Å) variation. The resistivity of BKFS exhibits variable range hopping behavior with ln(ρ) ~ T(-1/2) at low temperature. The magnetic susceptibility χ(T) exhibits a sharp cusp at around 20 K in a zero-field-cooled process. The frequency-dependent ac magnetic susceptibility reveals that the cusp feature is attributable to spin glass behavior. The anisotropic ac magnetic susceptibility indicates that BKFS is probably an anisotropic Heisenberg-like spin glass with its easy magnetization plane perpendicular to the chain direction. The specific heat also supports an insulating and spin glass ground state. Extended Curie-Weiss behavior above 40 K was observed with a reduced effective moment (μ(eff) = 1.66 μ(B)/Fe for H is perpendicular to b and μ(eff) = 1.82 μB/Fe for H is parallel to b) in BKFS, which is close to the spin-only magnetism with S=1/2.
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Affiliation(s)
- Jin-Ke Bao
- Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China
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8
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Otsuki J, Vollhardt D. Numerical solution of the t-J model with random exchange couplings in d=∞ dimensions. PHYSICAL REVIEW LETTERS 2013; 110:196407. [PMID: 23705729 DOI: 10.1103/physrevlett.110.196407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Indexed: 06/02/2023]
Abstract
To explore the nature of the metallic state near the transition to a Mott insulator, we investigate the t-J model with random exchange interaction in d=∞ dimensions. A numerically exact solution is obtained by an extension of the continuous-time quantum Monte Carlo method to the case of a vector bosonic field coupled to a local spin. We show that the paramagnetic solution near the Mott insulator describes an incoherent metal with a residual moment, and that single-particle excitations produce an additional band, which is separated from the Mott-Hubbard band.
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Affiliation(s)
- Junya Otsuki
- Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany
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9
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Huang TS, Chen CH, Tai MF. Studies on Crystal Structure and Magnetic Scaling Behavior of Perovskite-Like (La1−xPbx)MnO3 System with x = 0 - 0.5. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-674-u3.4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe magnetic critical behaviors in the perovskite-like (La1−xPbx)MnO3 series with x = 0.0 ∼ 0.5 are studied by means of dc magnetic measurements. All the samples crystallize in the rhombohedral unit cell with a C R 3 space group (a 0.54 nm and c 1.33 nm). The detailed crystallographic parameters of all the samples are obtained by the refinements of the powder x-ray diffraction data using the Rietveld method. The substitution effect of Pb2+ ions on La3+ sites induces a mixed-valence state of Mn3+/Mn4+ and enhances magnetic transition temperature in the (La1−xPbx)MnO3 system. The transition temperature TC increases with the Pb content from 225 K as x = 0 to 355 K as x = 0.5. The canonical spin-glass behaviors in low fields and the scaling behaviors of magnetic physical quantities are clearly observed in all our samples. The values of the related critical exponents and the scaling functions of magnetic data are close to those of the conventional spin glass systems.
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10
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Chen CH, Huang TS, Tai MF. Magnetic Properties and Scaling Behavior in Perovskite–like La0.7(Ba1−xPbx)0.3CoO3 System. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-674-u3.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTIn this study, we used x-ray diffraction patterns and dc magnetic measurements to investigate the crystallographic structure, magnetic properties and scaling behavior of the distorted perovskite La0.7(Ba1−xPbx)0.3CoO3 (0 ≤ x ≤ 0.5) system with a constant ratio of Co4+/Co3+. Samples with x = 0.0 and 0.1 were crystallized in the cubic structure with a ∼ 7.76 Å whereas samples with x ≥ 0.2 were crystallized in an orthorhombic Pbnm space group with a ∼ b ∼ 5.50 Å and c ∼ 7.85 Å. For all our samples the spin-glass-like behavior were observed in low temperature and low field ranges. The Pb2+ substitution on Ba2+ site does not significantly affect the ferromagnetic transition temperature TC, but does introduce large variation in the magnetic strength. In both the ferromagnetic and paramagnetic states the minimum values of the average effective moments provided by every Co ion occur at x = 0.3. We also observed the scaling behaviors of magnetic data in all samples. The derived values of the critical exponents (β, γ, δ) were consistent with those predicted by mean field theory and a three-dimensional Heisenberg model.
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Deng HY. Spin glass behaviors compatible with a Zhang-Rice singlet within an effective model for cuprate superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:075702. [PMID: 21817335 DOI: 10.1088/0953-8984/21/7/075702] [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
To address the incompatibility of Zhang-Rice singlet formation and the observed spin glass behavior, an effective model is proposed for the electronic behavior of cuprate materials. The model includes an antiferromagnetic interaction between the spin of the hole in a Zhang-Rice orbital and the spin of the hole on the corresponding copper site. While in the large interaction limit this recovers the t-J model, in the low energy limit the Zhang-Rice singlets are deformed. It is also shown that such deformation can induce random defect ferromagnetic (FM) bonds between adjacent local spins, an effect herein referred to as unusual double exchange, and then spin glass behavior shall result in the case of localized holes. A derivation of the model is also presented.
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Affiliation(s)
- Hai-Yao Deng
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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Mohottala HE, Wells BO, Budnick JI, Hines WA, Niedermayer C, Udby L, Bernhard C, Moodenbaugh AR, Chou FC. Phase separation in superoxygenated La2-xSrxCuO4+y. NATURE MATERIALS 2006; 5:377-82. [PMID: 16617346 DOI: 10.1038/nmat1633] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Accepted: 03/08/2006] [Indexed: 05/08/2023]
Abstract
The complex interplay between superconducting and magnetic phases remains poorly understood. Here, we report on the phase separation of doped holes into separate magnetic and superconducting regions in superoxygenated La(2-x)Sr(x)CuO(4+y), with various Sr contents. Irrespective of Sr-doping, excess oxygen raises the superconducting onset to 40 K with a coexisting magnetic spin-density wave that also orders near 40 K in each of our samples. The magnetic region is closely related to the anomalous, 1/8-hole-doped magnetic versions of La(2)CuO(4), whereas the superconducting region is optimally doped. The two phases are probably the only truly stable ground states in this region of the phase diagram. This simple two-component system is a candidate for electronic phase separation in cuprate superconductors, and a key to understanding seemingly conflicting experimental observations.
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Affiliation(s)
- Hashini E Mohottala
- University of Connecticut U-3046, 2152 Hillside Road, Storrs, Connecticut 06269-3046, USA
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13
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Park T, Nussinov Z, Hazzard KRA, Sidorov VA, Balatsky AV, Sarrao JL, Cheong SW, Hundley MF, Lee JS, Jia QX, Thompson JD. Novel dielectric anomaly in the hole-doped La(2)Cu(1-x)Li(x)O(4) and La(2-x)Sr(x)NiO(4) insulators: signature of an electronic glassy state. PHYSICAL REVIEW LETTERS 2005; 94:017002. [PMID: 15698121 DOI: 10.1103/physrevlett.94.017002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Indexed: 05/24/2023]
Abstract
The low-frequency dielectric response of hole-doped insulators La(2)Cu(1-x)Li(x)O(4) and La(2-x)Sr(x)NiO(4) shows a large dielectric constant epsilon(') at high temperature and a steplike drop by a factor of 100 at a material-dependent low temperature T(f). T(f) increases with frequency, and the dielectric response shows universal scaling in a Cole-Cole plot, suggesting that a charge-glass state is realized both in the cuprates and in the nickelates.
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Affiliation(s)
- Tuson Park
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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14
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Nair S, Banerjee A. Formation of finite antiferromagnetic clusters and the effect of electronic phase separation in Pr0.5Ca0.5Mn0.975Al0.025O3. PHYSICAL REVIEW LETTERS 2004; 93:117204. [PMID: 15447376 DOI: 10.1103/physrevlett.93.117204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Indexed: 05/24/2023]
Abstract
We report the first experimental evidence of a magnetic phase arising due to the thermal blocking of antiferromagnetic clusters in the weakened charge and orbital ordered system Pr0.5Ca0.5Mn0.975Al0.025O3. The third order susceptibility (chi(3)) is used to differentiate this transition from a spin- or cluster-glass-like freezing mechanism. These clusters are found to be mesoscopic and robust to electronic phase separation which only enriches the antiphase domain walls with holes at the cost of the bulk, without changing the size of these clusters.
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Affiliation(s)
- Sunil Nair
- Inter University Consortium for Department of Atomic Energy Facilities, University Campus, Khandwa Road, Indore, 452 017, India
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15
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Bellini T, Buscaglia M, Chiccoli C, Mantegazza F, Pasini P, Zannoni C. Nematics with quenched disorder: how long will it take to heal? PHYSICAL REVIEW LETTERS 2002; 88:245506. [PMID: 12059315 DOI: 10.1103/physrevlett.88.245506] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2002] [Indexed: 05/23/2023]
Abstract
Nematics with quenched disorder have been repeatedly predicted to form glass phases. Here we present turbidity experiments and computer simulations aimed at studying glass key features such as dynamics and history dependence in randomly perturbed nematics. Electric field-cooling alignment has been employed to prepare samples in suitably oriented starting states. Remarkable remnant order and slow dynamics are found both by experiment and simulations, indicating that random disorder can, by itself, induce a nematic glass state even without perturber restructuring.
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Affiliation(s)
- T Bellini
- INFM, Dipartimento di Chimica e Biochimica Medica, Università di Milano, 20133 Milan, Italy
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16
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Lavrov AN, Ando Y, Komiya S, Tsukada I. Unusual magnetic susceptibility anisotropy in untwinned La2-xSr(x)CuO4 single crystals in the lightly doped region. PHYSICAL REVIEW LETTERS 2001; 87:017007. [PMID: 11461491 DOI: 10.1103/physrevlett.87.017007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2001] [Indexed: 05/23/2023]
Abstract
We present a study of the magnetic susceptibility chi in carefully detwinned La 2-xSr(x)CuO4 single crystals in the lightly doped region (x = 0-0.03), which demonstrates a remarkable in-plane anisotropy of the spin system. This anisotropy, chi(a)/chi(b), is found to persist after the long-range antiferromagnetic (AF) order is destroyed by hole doping, suggesting that doped holes break the AF order into domains in which the spin alignment is kept essentially intact. It turns out that the freezing of the spins taking place at low temperatures is also notably anisotropic, implying that the "spin-glass" feature is governed by the domain structure as well.
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Affiliation(s)
- A N Lavrov
- Central Research Institute of Electric Power Industry, 2-11-1 Iwato-kita, Komae, Tokyo 201-8511 Japan
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18
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Julien M, Feher T, Horvatic M, Berthier C, Bakharev ON, Segransan P, Collin G, Marucco J. 63Cu NMR evidence for enhanced antiferromagnetic correlations around Zn impurities in YBa2Cu3O6.7. PHYSICAL REVIEW LETTERS 2000; 84:3422-3425. [PMID: 11019105 DOI: 10.1103/physrevlett.84.3422] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/1999] [Indexed: 05/23/2023]
Abstract
Doping the high- T(c) superconductor YBa2Cu3O6.7 with 1.5% of nonmagnetic Zn impurities in CuO2 planes is shown to produce a considerable broadening of 63Cu NMR spectra, as well as an increase of low-energy magnetic fluctuations detected in 63Cu spin-lattice relaxation measurements. A model-independent analysis demonstrates that these effects are due to the development of staggered magnetic moments on many Cu sites around each Zn and that the Zn-induced moment in the bulk susceptibility might be explained by this staggered magnetization. Several implications of these enhanced antiferromagnetic correlations are discussed.
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Affiliation(s)
- M Julien
- Grenoble High Magnetic Field Laboratory, CNRS and MPI-FKF,BP 166, F-38042 Grenoble Cedex 9, France and Laboratoire de Spectrometrie Physique, Universite J. Fourier, BP 87, F-38402 St. Martin d'Heres, France
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Schiffer P, Ramirez AP, Franklin KN, Cheong SW. Interaction-Induced Spin Coplanarity in a Kagomé Magnet: SrCr9pGa 12-9pO19. PHYSICAL REVIEW LETTERS 1996; 77:2085-2088. [PMID: 10061853 DOI: 10.1103/physrevlett.77.2085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Rosenow B, Oppermann R. Tricritical Behavior of Ising Spin Glasses with Charge Fluctuations. PHYSICAL REVIEW LETTERS 1996; 77:1608-1611. [PMID: 10063121 DOI: 10.1103/physrevlett.77.1608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Olejniczak J, Zaleski AJ. Spin-glass ordering of Fe-doped La2-xSrxCuO4. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:80-83. [PMID: 9984229 DOI: 10.1103/physrevb.54.80] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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