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Devi S, Biswas PK, Yokoyama K, Adroja DT, Yadav CS. Muon spin relaxation and emergence of disorder-induced unconventional dynamic magnetic fluctuations in Dy 2Zr 2O 7. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:345802. [PMID: 38749470 DOI: 10.1088/1361-648x/ad4c44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Accepted: 05/15/2024] [Indexed: 05/31/2024]
Abstract
The disordered pyrochlore oxide Dy2Zr2O7shows the signatures of field-induced spin freezing with remnant zero-point spin-ice entropy at 5 kOe magnetic field. We have performed zero-field and longitudinal field Muon spin relaxation (µSR) studies on Dy2Zr2O7. Our zero field studies reveal the absence of both long-range ordering and spin freezing down to 62 mK. TheµSR relaxation rate exhibits a temperature-independent plateau below 4 K, indicating a dynamic ground state of fluctuating spins similar to the well-known spin ice system Dy2Ti2O7. The low-temperature spin fluctuations persist in the longitudinal field of 20 kOe as well and show unusual field dependence of the relaxation rate, which is uncommon for a spin-liquid system. Our results, combined with the previous studies do not show any evidence of spin ice or spin glass ground state, rather point to a disorder-induced dynamic magnetic ground state in the Dy2Zr2O7material.
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Affiliation(s)
- Sheetal Devi
- School of Physical Sciences, Indian Institute of Technology Mandi, Mandi 175075, (H.P.), India
| | - Pabitra K Biswas
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - K Yokoyama
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - D T Adroja
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - C S Yadav
- School of Physical Sciences, Indian Institute of Technology Mandi, Mandi 175075, (H.P.), India
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2
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Kermarrec E, Kumar R, Bernard G, Hénaff R, Mendels P, Bert F, Paulose PL, Hazra BK, Koteswararao B. Classical Spin Liquid State in the S=5/2 Heisenberg Kagome Antiferromagnet Li_{9}Fe_{3}(P_{2}O_{7})_{3}(PO_{4})_{2}. PHYSICAL REVIEW LETTERS 2021; 127:157202. [PMID: 34678038 DOI: 10.1103/physrevlett.127.157202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/14/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
We investigate the low temperature magnetic properties of a S=5/2 Heisenberg kagome antiferromagnet, the layered monodiphosphate Li_{9}Fe_{3}(P_{2}O_{7})_{3}(PO_{4})_{2}, using magnetization measurements and ^{31}P nuclear magnetic resonance. An antiferromagnetic-type order sets in at T_{N}=1.3 K and a characteristic magnetization plateau is observed at 1/3 of the saturation magnetization below T^{*}∼5 K. A moderate ^{31}P NMR line broadening reveals the development of anisotropic short-range correlations concomitantly with a gapless spin-lattice relaxation time T_{1}∼k_{B}T/ℏS, which may point to the presence of a semiclassical nematic spin-liquid state predicted for the Heisenberg kagome antiferromagnetic model or to the persistence of the zero-energy modes of the kagome lattice under large magnetic fields.
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Affiliation(s)
- E Kermarrec
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - R Kumar
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - G Bernard
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - R Hénaff
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - P Mendels
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - F Bert
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - P L Paulose
- Department of Condensed Matter Physics and Materials Science, TIFR, Mumbai 400 005, India
| | - B K Hazra
- School of Physics, University of Hyderabad, Hyderabad 500046, India
| | - B Koteswararao
- Department of Physics, Indian Institute of Technology Tirupati, Tirupati 517506, India
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Liu T, Li W, Su G. Spin-ordered ground state and thermodynamic behaviors of the spin-3/2 kagome Heisenberg antiferromagnet. Phys Rev E 2016; 94:032114. [PMID: 27739841 DOI: 10.1103/physreve.94.032114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Indexed: 06/06/2023]
Abstract
Three different tensor network (TN) optimization algorithms are employed to accurately determine the ground state and thermodynamic properties of the spin-3/2 kagome Heisenberg antiferromagnet. We found that the sqrt[3]×sqrt[3] state (i.e., the state with 120^{∘} spin configuration within a unit cell containing 9 sites) is the ground state of this system, and such an ordered state is melted at any finite temperature, thereby clarifying the existing experimental controversies. Three magnetization plateaus (m/m_{s}=1/3,23/27, and 25/27) were obtained, where the 1/3-magnetization plateau has been observed experimentally. The absence of a zero-magnetization plateau indicates a gapless spin excitation that is further supported by the thermodynamic asymptotic behaviors of the susceptibility and specific heat. At low temperatures, the specific heat is shown to exhibit a T^{2} behavior, and the susceptibility approaches a finite constant as T→0. Our TN results of thermodynamic properties are compared with those from high-temperature series expansion. In addition, we disclose a quantum phase transition between q=0 state (i.e., the state with 120^{∘} spin configuration within a unit cell containing three sites) and sqrt[3]×sqrt[3] state in a spin-3/2 kagome XXZ model at the critical point Δ_{c}=0.54. This study provides reliable and useful information for further explorations on high-spin kagome physics.
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Affiliation(s)
- Tao Liu
- Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049, China
| | - Wei Li
- Department of Physics, Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education), Beihang University, Beijing 100191, China
- International Research Institute of Multidisciplinary Science, Beihang University, Beijing 100191, China
| | - Gang Su
- Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049, China
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Li Y, Adroja D, Biswas PK, Baker PJ, Zhang Q, Liu J, Tsirlin AA, Gegenwart P, Zhang Q. Muon Spin Relaxation Evidence for the U(1) Quantum Spin-Liquid Ground State in the Triangular Antiferromagnet YbMgGaO_{4}. PHYSICAL REVIEW LETTERS 2016; 117:097201. [PMID: 27610879 DOI: 10.1103/physrevlett.117.097201] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Indexed: 06/06/2023]
Abstract
Muon spin relaxation (μSR) experiments on single crystals of the structurally perfect triangular antiferromagnet YbMgGaO_{4} indicate the absence of both static long-range magnetic order and spin freezing down to 0.048 K in a zero field. Below 0.4 K, the μ^{+} spin relaxation rates, which are proportional to the dynamic correlation function of the Yb^{3+} spins, exhibit temperature-independent plateaus. All these μSR results unequivocally support the formation of a gapless U(1) quantum spin liquid ground state in the triangular antiferromagnet YbMgGaO_{4}.
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Affiliation(s)
- Yuesheng Li
- Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Devashibhai Adroja
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa
| | - Pabitra K Biswas
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Peter J Baker
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Qian Zhang
- Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China
| | - Juanjuan Liu
- Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China
| | - Alexander A Tsirlin
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Philipp Gegenwart
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Qingming Zhang
- Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People's Republic of China
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Khuntia P, Bert F, Mendels P, Koteswararao B, Mahajan AV, Baenitz M, Chou FC, Baines C, Amato A, Furukawa Y. Spin Liquid State in the 3D Frustrated Antiferromagnet PbCuTe_{2}O_{6}: NMR and Muon Spin Relaxation Studies. PHYSICAL REVIEW LETTERS 2016; 116:107203. [PMID: 27015508 DOI: 10.1103/physrevlett.116.107203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Indexed: 06/05/2023]
Abstract
PbCuTe_{2}O_{6} is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu^{2+} ions although additional interactions enhance the magnetic lattice connectivity. Through a combination of magnetization measurements and local probe investigations by NMR and muon spin relaxation down to 20 mK, we provide robust evidence for the absence of magnetic freezing in the ground state. The local spin susceptibility probed by the NMR shift hardly deviates from the macroscopic one down to 1 K pointing to a homogeneous magnetic system with a low defect concentration. The saturation of the NMR shift and the sublinear power law temperature (T) evolution of the 1/T_{1} NMR relaxation rate at low T point to a nonsinglet ground state favoring a gapless fermionic description of the magnetic excitations. Below 1 K a pronounced slowing down of the spin dynamics is witnessed, which may signal a reconstruction of spinon Fermi surface. Nonetheless, the compound remains in a fluctuating spin liquid state down to the lowest temperature of the present investigation.
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Affiliation(s)
- P Khuntia
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA
- Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - F Bert
- Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - P Mendels
- Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - B Koteswararao
- School of Physics, University of Hyderabad, Central University PO, Hyderabad 500046, India
- Center of Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - A V Mahajan
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
| | - M Baenitz
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - F C Chou
- Center of Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - C Baines
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - A Amato
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Y Furukawa
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
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Iida K, Lee SH, Cheong SW. Coexisting order and disorder hidden in a quasi-two-dimensional frustrated magnet. PHYSICAL REVIEW LETTERS 2012; 108:217207. [PMID: 23003299 DOI: 10.1103/physrevlett.108.217207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Indexed: 06/01/2023]
Abstract
Frustrated magnetic interactions in a quasi-two-dimensional [111] slab of pyrochlore lattice were studied. For uniform nearest neighbor (NN) interactions, we show that the complex magnetic problem can be mapped onto a model with two independent degrees of freedom, tricolor and binary sign. This provides a systematic way to construct the complex classical spin ground states with collinear and coplanar bipyramid spins. We also identify "partial but extended" zero-energy excitations amongst the ground states. For nonuniform NN interactions, the coplanar ground state can be obtained from the collinear bipyramid spin state by collectively rotating two spins of each tetrahedron with an angle α in an opposite direction. The latter model with α~30° fits the experimental neutron data from SrCr(9p)Ga(12-9p)O(19) well.
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Affiliation(s)
- K Iida
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
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7
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Lhuillier C, Misguich G. Introduction to Quantum Spin Liquids. INTRODUCTION TO FRUSTRATED MAGNETISM 2011. [DOI: 10.1007/978-3-642-10589-0_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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9
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Kagomé Antiferromagnets: Materials Vs. Spin Liquid Behaviors. INTRODUCTION TO FRUSTRATED MAGNETISM 2011. [DOI: 10.1007/978-3-642-10589-0_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Zorko A, Bert F, Mendels P, Bordet P, Lejay P, Robert J. Easy-axis kagome antiferromagnet: local-probe study of Nd3Ga5SiO14. PHYSICAL REVIEW LETTERS 2008; 100:147201. [PMID: 18518066 DOI: 10.1103/physrevlett.100.147201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/01/2008] [Indexed: 05/26/2023]
Abstract
We report a local-probe investigation of the magnetically anisotropic kagome compound Nd3Ga5SiO14. Our zero-field muon spin relaxation (muSR) results provide direct evidence of a fluctuating collective paramagnetic state down to 60 mK, supported by a wipeout of the Ga nuclear magnetic resonance (NMR) signal below 25 K. At 60 mK a dynamics crossover to a much more static state is observed by muSR in magnetic fields above 0.5 T. Accordingly, the NMR signal is recovered at low T above a threshold field, revealing a rapid temperature and field variation of the magnetic fluctuations.
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Affiliation(s)
- A Zorko
- Laboratoire de Physique des Solides, Université Paris-Sud 11, UMR CNRS 8502, 91405 Orsay, France
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11
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Mendels P, Bert F, de Vries MA, Olariu A, Harrison A, Duc F, Trombe JC, Lord JS, Amato A, Baines C. Quantum magnetism in the paratacamite family: towards an ideal kagomé lattice. PHYSICAL REVIEW LETTERS 2007; 98:077204. [PMID: 17359056 DOI: 10.1103/physrevlett.98.077204] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Indexed: 05/14/2023]
Abstract
We report muon spin rotation measurements on the S=1/2 (Cu2+) paratacamite ZnxCu4-x(OH)6Cl2 family. Despite a Weiss temperature of approximately -300 K, the x=1 compound is found to have no transition to a magnetic frozen state down to 50 mK as theoretically expected for the kagomé Heisenberg antiferromagnet. We find that the limit between a dynamical and a partly frozen ground state occurs around x=0.5. For x=1, we discuss the relevance to a singlet picture.
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Affiliation(s)
- P Mendels
- Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France
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12
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Bert F, Mendels P, Olariu A, Blanchard N, Collin G, Amato A, Baines C, Hillier AD. Direct evidence for a dynamical ground state in the highly frustrated Tb(2)Sn(2)O(7) pyrochlore. PHYSICAL REVIEW LETTERS 2006; 97:117203. [PMID: 17025926 DOI: 10.1103/physrevlett.97.117203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Indexed: 05/12/2023]
Abstract
mSR experiments have been performed on a powder sample of the "ordered spin ice" Tb(2)Sn(2)O(7) pyrochlore. At base temperature (T=35 mK), the muon relaxation is found to be of dynamical nature, which demonstrates that strong fluctuations persist below the ferromagnetic transition (T(C)=0.87 K). Hints of long-range ordering appear as oscillations of the muon polarization when an external field is applied and also as a hysteretic behavior below T(C). We propose that dynamics results from fluctuations of clusters of correlated spins with the ordered spin ice structure.
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Affiliation(s)
- F Bert
- Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France
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Mutka H, Ehlers G, Payen C, Bono D, Stewart JR, Fouquet P, Mendels P, Mevellec JY, Blanchard N, Collin G. Neutron spin-echo investigation of slow spin dynamics in kagomé-bilayer frustrated magnets as evidence for phonon assisted relaxation in SrCr9xGa12-9xO19. PHYSICAL REVIEW LETTERS 2006; 97:047203. [PMID: 16907610 DOI: 10.1103/physrevlett.97.047203] [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: 05/11/2023]
Abstract
A neutron spin-echo investigation of the low temperature spin dynamics in two well-characterized kagomé bilayer compounds SrCr9xGa12-9xO19 (x=0.95, SCGO) and Ba2Sn2ZnCr7xGa10-7xO22 (x=0.97, BSZCGO) reveals two novel features. One is the slowing down of the relaxation rate without critical behavior at Tg, where a macroscopic spin-glass-like freezing occurs. The second is, in SCGO at 4 K (approximately Tg)<T<7 K, the relaxation rate activation energy Ea=7+/-0.4 meV, equal to the energy of a phonon mode, pointing out the role of spin-lattice coupling.
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Affiliation(s)
- H Mutka
- Institut Laue-Langevin, Boîte Postale 156X, F-38042 Grenoble Cedex 9, France.
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Bert F, Bono D, Mendels P, Ladieu F, Duc F, Trombe JC, Millet P. Ground state of the kagomé-like S=1/2 antiferromagnet volborthite Cu3V2O7(OH)2 x 2H2O. PHYSICAL REVIEW LETTERS 2005; 95:087203. [PMID: 16196896 DOI: 10.1103/physrevlett.95.087203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Indexed: 05/04/2023]
Abstract
The volborthite compound is one of the very few realizations of S=1/2 quantum spins on a highly frustrated kagomé-like lattice. Low-T SQUID measurements reveal a broad magnetic transition below 2 K which is further confirmed by a peak in the 51V nuclear spin relaxation rate (1/T1) at 1.4 K +/- 0.2 K. Through 51V NMR, the ground state (GS) appears to be a mixture of different spin configurations, among which 20% corresponds to a well defined short-range order, possibly of the sqrt(3) x sqrt(3) type. While the freezing involves all the Cu2+ spins, only 40% of the copper moment is actually frozen which suggests that quantum fluctuations strongly renormalize the GS.
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Affiliation(s)
- F Bert
- Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France
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Zheng XG, Kubozono H, Nishiyama K, Higemoto W, Kawae T, Koda A, Xu CN. Coexistence of long-range order and spin fluctuation in geometrically frustrated clinoatacamite Cu2Cl(OH)3. PHYSICAL REVIEW LETTERS 2005; 95:057201. [PMID: 16090912 DOI: 10.1103/physrevlett.95.057201] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 05/01/2005] [Indexed: 05/03/2023]
Abstract
Muon spin rotation experiments are carried out on clinoatacamite, Cu2Cl(OH)3, which is a new geometrically frustrated system featuring a three-dimensional network of corner-sharing tetrahedral 3d Cu2+ spins. A long-range antiferromagnetic order occurs below 18.1 K with a surprisingly small entropy release of about 0.05Rln2/Cu. Below 6.5 K, the static long-range order transforms abruptly into a metastable state with nearly complete depolarization of muon spins which suggests strong fluctuation. The system then enters a state in which partial long-range order and spin fluctuation coexist down to the lowest experimentally attainable temperature of 20 mK. This work presents a novel system for studying geometric frustration.
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Affiliation(s)
- X G Zheng
- Department of Physics, Faculty of Science and Engineering, Saga University, Saga 840-8502, Japan.
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Yaouanc A, de Réotier PD, Glazkov V, Marin C, Bonville P, Hodges JA, Gubbens PCM, Sakarya S, Baines C. Magnetic density of states at low energy in geometrically frustrated systems. PHYSICAL REVIEW LETTERS 2005; 95:047203. [PMID: 16090837 DOI: 10.1103/physrevlett.95.047203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Indexed: 05/03/2023]
Abstract
Using muon-spin-relaxation measurements we show that the pyrochlore compound Gd(2)Ti(2)O(7), in its magnetically ordered phase below approximately 1 K, displays persistent spin dynamics down to temperatures as low as 20 mK. The characteristics of the induced muon relaxation can be accounted for by a scattering process involving two magnetic excitations, with a density of states characterized by an upturn at low energy and a small gap depending linearly on the temperature. We propose that such a density of states is a generic feature of geometrically frustrated magnetic materials.
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Affiliation(s)
- A Yaouanc
- CEA/DSM/Département de Recherche Fondamentale sur la Matière Condensée, Grenoble, France
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