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Jiang N, Zhou J, Hao XL, Li J, Zhang D, Bacsa J, Choi ES, Ramanathan A, Baumbach RE, Li H, Brédas JL, Han Y, La Pierre HS. Ground-State Spin Dynamics in d1 Kagome-Lattice Titanium Fluorides. J Am Chem Soc 2023; 145:207-215. [PMID: 36534963 DOI: 10.1021/jacs.2c09633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Many quantum magnetic materials suffer from structural imperfections. The effects of structural disorder on bulk properties are difficult to assess systematically from a chemical perspective due to the complexities of chemical synthesis. The recently reported S = 1/2 kagome lattice antiferromagnet, (CH3NH3)2NaTi3F12, 1-Ti, with highly symmetric kagome layers and disordered interlayer methylammonium cations, shows no magnetic ordering down to 0.1 K. To study the impact of structural disorder in the titanium fluoride kagome compounds, (CH3NH3)2KTi3F12, 2-Ti, was prepared. It presents no detectable structural disorder and only a small degree of distortion of the kagome lattice. The methylammonium disorder model of 1-Ti and order in 2-Ti were confirmed by atomic-resolution transmission electron microscopy. The antiferromagnetic interactions and band structures of both compounds were calculated based on spin-polarized density functional theory and support the magnetic structure analysis. Three spin-glass-like (SGL) transitions were observed in 2-Ti at 0.5, 1.4, and 2.3 K, while a single SGL transition can be observed in 1-Ti at 0.8 K. The absolute values of the Curie-Weiss temperatures of both 1-Ti (-139.5(7) K) and 2-Ti (-83.5(7) K) are larger than the SGL transition temperatures, which is indicative of geometrically frustrated spin glass (GFSG) states. All the SGL transitions are quenched with an applied field >0.1 T, which indicates novel magnetic phases emerge under small applied magnetic fields. The well-defined structure and the lack of structural disorder in 2-Ti suggest that 2-Ti is an ideal model compound for studying GFSG states and the potential transitions between spin liquid and GFSG states.
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Affiliation(s)
- Ningxin Jiang
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332-0400, United States
| | - Jinfei Zhou
- Multi-scale Porous Materials Center, Institute of Advanced Interdisciplinary Studies & School of Chemistry and Chemical Engineering, Chongqing University, Chongqing400044, P. R. China
| | - Xue-Li Hao
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332-0400, United States
| | - Jingwei Li
- Multi-scale Porous Materials Center, Institute of Advanced Interdisciplinary Studies & School of Chemistry and Chemical Engineering, Chongqing University, Chongqing400044, P. R. China
| | - Daliang Zhang
- Multi-scale Porous Materials Center, Institute of Advanced Interdisciplinary Studies & School of Chemistry and Chemical Engineering, Chongqing University, Chongqing400044, P. R. China
| | - John Bacsa
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332-0400, United States
| | - Eun Sang Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Arun Ramanathan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332-0400, United States
| | - Ryan E Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Hong Li
- Department of Chemistry & Biochemistry, The University of Arizona, Tucson, Arizona85721-0088, United States
| | - Jean-Luc Brédas
- Department of Chemistry & Biochemistry, The University of Arizona, Tucson, Arizona85721-0088, United States
| | - Yu Han
- Physical Sciences and Engineering Division, Advanced Membranes and Porous Materials (AMPM) Center, King Abdullah University of Science and Technology (KAUST), Thuwal23955-6900, Saudi Arabia
| | - Henry S La Pierre
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332-0400, United States.,Nuclear and Radiological Engineering and Medical Physics Program, School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia30332-0400, United States
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2
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Hu X, Pajerowski DM, Zhang D, Podlesnyak AA, Qiu Y, Huang Q, Zhou H, Klich I, Kolesnikov AI, Stone MB, Lee SH. Freezing of a Disorder Induced Spin Liquid with Strong Quantum Fluctuations. PHYSICAL REVIEW LETTERS 2021; 127:017201. [PMID: 34270292 PMCID: PMC10424116 DOI: 10.1103/physrevlett.127.017201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/26/2021] [Accepted: 06/03/2021] [Indexed: 06/13/2023]
Abstract
Sr_{2}CuTe_{0.5}W_{0.5}O_{6} is a square-lattice magnet with superexchange between S=1/2Cu^{2+} spins mediated by randomly distributed Te and W ions. Here, using sub-K temperature and 20 μeV energy resolution neutron scattering experiments we show that this system transits from a gapless disorder-induced spin liquid to a new quantum state below T_{f}=1.7(1) K, exhibiting a weak frozen moment of ⟨S⟩/S∼0.1 and low energy dynamic susceptibility, χ^{''}(ℏω), linear in energy which is surprising for such a weak freezing in this highly fluctuating quantum regime.
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Affiliation(s)
- Xiao Hu
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Daniel M. Pajerowski
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Depei Zhang
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Andrey A. Podlesnyak
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Yiming Qiu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Qing Huang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Haidong Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Israel Klich
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | | | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Seung-Hun Lee
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
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Zhang B, Wu L, Feng X, Li C, Miao X, Hui Y, Zhao K, Ding J, Jin B, Chen J, Zhu Y, Sun CJ, Chow GM. Tuning Irreversible Magnetoresistance in Pr 0.67Sr 0.33MnO 3 Film via Octahedral Rotation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:43222-43230. [PMID: 32820885 DOI: 10.1021/acsami.0c10402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The oxygen octahedral rotation around the out-of-plane axis is explored to study its effect on metastable status, magnetic cluster glass in manganite. The antiphase rotation around the out-of-plane axis (TiO6 a0a0c-) of SrTiO3 enhances the Mn-O bond anisotropy along in-plane and out-of-plane directions and weakens the ferromagnetic interactions in a 12 nm Pr0.67Sr0.33MnO3 film on the (001) SrTiO3 substrate, which together promote the formation of magnetic cluster-glassiness and enlarges the irreversible magnetoresistance (MR) effect with enhanced relaxation time of charge carriers. The effect of TiO6 a0a0c- in the SrTiO3 substrate on material properties is obvious with a large irreversible MR effect for thin films, which fades away with the increase in film thickness. At 10 K, the irreversible MR is 0.91 for the 12 nm film and 0.22 for the 30 nm film. This work extends current understanding on interfacial coupling to metastable status and could help explore other systems in the perovskite structure with octahedral rotation.
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Affiliation(s)
- Bangmin Zhang
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Lijun Wu
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Xin Feng
- Department of Materials Science & Engineering, National University of Singapore, 117575, Singapore
| | - Chun Li
- Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Xinyang Miao
- Petroleum and Chemical Industry Federation Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection, China University of Petroleum, Beijing 102249, China
| | - Yajuan Hui
- Department of Materials Science & Engineering, National University of Singapore, 117575, Singapore
| | - Kun Zhao
- Petroleum and Chemical Industry Federation Key Laboratory of Oil and Gas Terahertz Spectroscopy and Photoelectric Detection, China University of Petroleum, Beijing 102249, China
| | - Jun Ding
- Department of Materials Science & Engineering, National University of Singapore, 117575, Singapore
| | - Biaobing Jin
- Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Jingsheng Chen
- Department of Materials Science & Engineering, National University of Singapore, 117575, Singapore
| | - Yimei Zhu
- Condensed Matter Physics & Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Cheng-Jun Sun
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Gan Moog Chow
- Department of Materials Science & Engineering, National University of Singapore, 117575, Singapore
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Abstract
Glassiness is ubiquitous and diverse in characteristics in nature. Understanding their differences and classification remains a major scientific challenge. Here, we show that scaling of magnetic memories with time can be used to classify magnetic glassy materials into two distinct classes. The systems studied are high temperature superconductor-related materials, spin-orbit Mott insulators, frustrated magnets, and dilute magnetic alloys. Our bulk magnetization measurements reveal that most densely populated magnets exhibit similar memory behavior characterized by a relaxation exponent of \documentclass[12pt]{minimal}
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\begin{document}$$1-n\approx 0.6(1)$$\end{document}1−n≈0.6(1). This exponent is different from \documentclass[12pt]{minimal}
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\begin{document}$$1-{\boldsymbol{n}}\approx 1/3$$\end{document}1−n≈1/3 of dilute magnetic alloys that was ascribed to their hierarchical and fractal energy landscape, and is also different from \documentclass[12pt]{minimal}
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\begin{document}$$1-{\boldsymbol{n}}=1$$\end{document}1−n=1 of the conventional Debye relaxation expected for a spin solid, a state with long range order. Furthermore, our systematic study on dilute magnetic alloys with varying magnetic concentration exhibits crossovers among the two glassy states and spin solid.
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Abstract
The notion of complex energy landscape underpins the intriguing dynamical behaviors in many complex systems ranging from polymers, to brain activity, to social networks and glass transitions. The spin glass state found in dilute magnetic alloys has been an exceptionally convenient laboratory frame for studying complex dynamics resulting from a hierarchical energy landscape with rugged funnels. Here, we show, by a bulk susceptibility and Monte Carlo simulation study, that densely populated frustrated magnets in a spin jam state exhibit much weaker memory effects than spin glasses, and the characteristic properties can be reproduced by a nonhierarchical landscape with a wide and nearly flat but rough bottom. Our results illustrate that the memory effects can be used to probe different slow dynamics of glassy materials, hence opening a window to explore their distinct energy landscapes.
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Rau JG, Gingras MJP. Spin slush in an extended spin ice model. Nat Commun 2016; 7:12234. [PMID: 27470199 PMCID: PMC4974571 DOI: 10.1038/ncomms12234] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 06/14/2016] [Indexed: 11/09/2022] Open
Abstract
We present a new classical spin liquid on the pyrochlore lattice by extending spin ice with further neighbour interactions. We find that this disorder-free spin model exhibits a form of dynamical heterogeneity with extremely slow relaxation for some spins, while others fluctuate quickly down to zero temperature. We thus call this state spin slush, in analogy to the heterogeneous mixture of solid and liquid water. This behaviour is driven by the structure of the ground-state manifold which extends the celebrated two-in/two-out ice states to include branching structures built from three-in/one-out, three-out/one-in and all-in/all-out tetrahedra defects. Distinctive liquid-like patterns in the magnetic correlations serve as a signature of this intermediate range order. Possible applications to materials as well the effects of quantum tunnelling are discussed.
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Affiliation(s)
- Jeffrey G. Rau
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Michel J. P. Gingras
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
- Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada N2L 2Y5
- Canadian Institute for Advanced Research, 180 Dundas Street West, Suite 1400, Toronto, Ontario, Canada M5G 1Z8
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Abstract
Since the discovery of spin glasses in dilute magnetic systems, their study has been largely focused on understanding randomness and defects as the driving mechanism. The same paradigm has also been applied to explain glassy states found in dense frustrated systems. Recently, however, it has been theoretically suggested that different mechanisms, such as quantum fluctuations and topological features, may induce glassy states in defect-free spin systems, far from the conventional dilute limit. Here we report experimental evidence for existence of a glassy state, which we call a spin jam, in the vicinity of the clean limit of a frustrated magnet, which is insensitive to a low concentration of defects. We have studied the effect of impurities on SrCr9pGa12-9pO19 [SCGO(p)], a highly frustrated magnet, in which the magnetic Cr(3+) (s = 3/2) ions form a quasi-2D triangular system of bipyramids. Our experimental data show that as the nonmagnetic Ga(3+) impurity concentration is changed, there are two distinct phases of glassiness: an exotic glassy state, which we call a spin jam, for the high magnetic concentration region (p > 0.8) and a cluster spin glass for lower magnetic concentration (p < 0.8). This observation indicates that a spin jam is a unique vantage point from which the class of glassy states of dense frustrated magnets can be understood.
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Woo N, Silevitch DM, Ferri C, Ghosh S, Rosenbaum TF. Interplay of disorder and geometrical frustration in doped gadolinium gallium garnet. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:296001. [PMID: 26154501 DOI: 10.1088/0953-8984/27/29/296001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The geometrically frustrated triangular antiferromagnet Gadolinium Gallium Garnet (Gd3Ga5O12 or GGG) exhibits a rich mix of short-range order and isolated quantum states. We investigate the effects of up to 1% neodymium substitution for gallium on the ac magnetic response at temperatures below 1 K in both the linear and nonlinear regimes. Substitutional disorder actually drives the system toward a more perfectly frustrated state, apparently compensating for the effects of imperfect gadolinium/gallium stoichiometry, while at the same time more closely demarcating the boundaries of isolated, coherent clusters composed of hundreds of spins. Optical measurements of the local Nd environment substantiate the picture of an increased frustration index with doping.
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Affiliation(s)
- N Woo
- The James Franck Institute and Department of Physics, The University of Chicago, Chicago, IL 60637, USA
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