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Roy N, Mahato PC, Saha S, Telling M, Lord JS, Adroja DT, Banerjee SS. Probing the strongly correlated magnetic state of Co 2C nanoparticles at low temperatures using μSR. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:085603. [PMID: 37918015 DOI: 10.1088/1361-648x/ad08ec] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 11/01/2023] [Indexed: 11/04/2023]
Abstract
Co2C nanoparticles (NPs) are amongst transition metal carbides whose magnetic properties have not been well explored. An earlier study (Royet al2021J. Phys.: Condens. Matter33375804) showed that a pellet made from Co2C NPs exhibits exchange bias (EB) effect below a temperature,TEB= 50 K and a spin glass (SG) feature emerges belowTSG= 5 K. In the current study we use magnetic, electrical transport, specific heat, and muon spin rotation (μSR) measurements to explore further the magnetic properties of a pellet made with 40 nm diameter pure Co2C NPs. We uncover the onset of Kondo localization at Kondo temperatureTK(= 40.1 K), which is close to the onset temperature (TEB) of the EB effect. A crossover from the Kondo-screened scenario to the Ruderman-Kittel-Kasuya-Yosida interaction-dominated regime is also observed forT
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Affiliation(s)
- Nirmal Roy
- Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - P C Mahato
- Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Suprotim Saha
- Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - M Telling
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
| | - J S Lord
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
| | - D T Adroja
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot Oxon OX11 0QX, United Kingdom
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa
| | - S S Banerjee
- Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
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2
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Kundu S, Hossain A, S PK, Das R, Baenitz M, Baker PJ, Orain JC, Joshi DC, Mathieu R, Mahadevan P, Pujari S, Bhattacharjee S, Mahajan AV, Sarma DD. Signatures of a Spin-1/2 Cooperative Paramagnet in the Diluted Triangular Lattice of Y_{2}CuTiO_{6}. PHYSICAL REVIEW LETTERS 2020; 125:117206. [PMID: 32975979 DOI: 10.1103/physrevlett.125.117206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/11/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
We present a combination of thermodynamic and dynamic experimental signatures of a disorder driven dynamic cooperative paramagnet in a 50% site diluted triangular lattice spin-1/2 system: Y_{2}CuTiO_{6}. Magnetic ordering and spin freezing are absent down to 50 mK, far below the Curie-Weiss scale (-θ_{CW}) of ∼134 K. We observe scaling collapses of the magnetic field and temperature dependent magnetic heat capacity and magnetization data, respectively, in conformity with expectations from the random singlet physics. Our experiments establish the suppression of any freezing scale, if at all present, by more than 3 orders of magnitude, opening a plethora of interesting possibilities such as disorder stabilized long range quantum entangled ground states.
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Affiliation(s)
- S Kundu
- Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Akmal Hossain
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Pranava Keerthi S
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Ranjan Das
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India
| | - M Baenitz
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Peter J Baker
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire OX110QX, United Kingdom
| | | | - D C Joshi
- Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden
| | - Roland Mathieu
- Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden
| | - Priya Mahadevan
- S. N. Bose National Center for Basic Sciences, Block-JD, Salt Lake, Kolkata-700106, India
| | - Sumiran Pujari
- Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Subhro Bhattacharjee
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560089, India
| | - A V Mahajan
- Department of Physics, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - D D Sarma
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bengaluru 560012, India
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3
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Zhang W, Zhang L, Wong PKJ, Yuan J, Vinai G, Torelli P, van der Laan G, Feng YP, Wee ATS. Magnetic Transition in Monolayer VSe 2 via Interface Hybridization. ACS NANO 2019; 13:8997-9004. [PMID: 31306576 DOI: 10.1021/acsnano.9b02996] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Magnetism in monolayer (ML) VSe2 has attracted broad interest in spintronics, while existing reports have not reached consensus. Using element-specific X-ray magnetic circular dichroism, a magnetic transition in ML VSe2 has been demonstrated at the contamination-free interface between Co and VSe2. Through interfacial hybridization with a Co atomic overlayer, a magnetic moment of about 0.4 μB per V atom in ML VSe2 is revealed, approaching values predicted by previous theoretical calculations. Promotion of the ferromagnetism in ML VSe2 is accompanied by its antiferromagnetic coupling to Co and a reduction in the spin moment of Co. In comparison to the absence of this interface-induced ferromagnetism at the Fe/ML MoSe2 interface, these findings at the Co/ML VSe2 interface provide clear proof that the ML VSe2, initially with magnetic disorder, is on the verge of magnetic transition.
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Affiliation(s)
- Wen Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
| | - Lei Zhang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
| | - Ping Kwan Johnny Wong
- Centre for Advanced 2D Materials and Graphene Research Centre , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Jiaren Yuan
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
| | - Giovanni Vinai
- Laboratorio TASC , IOM-CNR , S.S. 14 km 163.5, Basovizza , 34149 Trieste , Italy
| | - Piero Torelli
- Laboratorio TASC , IOM-CNR , S.S. 14 km 163.5, Basovizza , 34149 Trieste , Italy
| | - Gerrit van der Laan
- Magnetic Spectroscopy Group , Diamond Light Source , Didcot OX11 0DE , United Kingdom
| | - Yuan Ping Feng
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
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Indra A, Dey K, Bhattacharyya A, Berlie A, Giri S. Unveiling spin-glass transition and antiferromagnetic order by μSR studies in spin-chain Sm 2BaNiO 5. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:165801. [PMID: 30681979 DOI: 10.1088/1361-648x/ab01e6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report the zero-field and longitudinal field muon spin relaxation studies in a spin-chain compound Sm2BaNiO5. Two magnetic transitions, that have not been previously detected by the heat capacity and magnetization measurements, are confirmed at 46 and 9 K. The antiferromagnetic order is suggested at 46 K. Analysis of the muon spin polarization unveils the spin-glass transition at 9 K. Time-field scaling relation of the muon spin polarization verifies the spin-spin autocorrelation function following the cut-off power law, which is approximated by the Ogielski form, as employed numerically for characterizing the spin-glasses.
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Affiliation(s)
- A Indra
- School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India. Department of Physics, Srikrishna College, Bagula, Nadia, W. B., 741502, India
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Dally R, Hogan T, Amato A, Luetkens H, Baines C, Rodriguez-Rivera J, Graf MJ, Wilson SD. Short-range correlations in the magnetic ground state of Na₄Ir₃O₈. PHYSICAL REVIEW LETTERS 2014; 113:247601. [PMID: 25541804 DOI: 10.1103/physrevlett.113.247601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Indexed: 06/04/2023]
Abstract
The magnetic ground state of the J(eff)=1/2 hyperkagome lattice in Na₄Ir₃O₈ is explored via combined bulk magnetization, muon spin relaxation, and neutron scattering measurements. A short-range, frozen state comprised of quasistatic moments develops below a characteristic temperature of T(F)=6 K, revealing an inhomogeneous distribution of spins occupying the entirety of the sample volume. Quasistatic, short-range spin correlations persist until at least 20 mK and differ substantially from the nominally dynamic response of a quantum spin liquid. Our data demonstrate that an inhomogeneous magnetic ground state arises in Na₄Ir₃O₈ driven either by disorder inherent to the creation of the hyperkagome lattice itself or stabilized via quantum fluctuations.
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Affiliation(s)
- Rebecca Dally
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Tom Hogan
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Alex Amato
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Hubertus Luetkens
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Chris Baines
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Jose Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Michael J Graf
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Stephen D Wilson
- Department of Materials, University of California, Santa Barbara, California 93106, USA
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Guo H, Xing H, Tong J, Tao Q, Watanabe I, Xu ZA. Possible spin frustration in Nd2Ti2O7 probed by muon spin relaxation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:436002. [PMID: 25299956 DOI: 10.1088/0953-8984/26/43/436002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Muon spin relaxation on Nd2Ti2O7 (NTO) and NdLaTi2O7 (NLTO) compounds are presented. The time spectra for both compounds are as expected for the paramagnetic state at high temperatures, but deviate from the exponential function below around 100 K. Firstly, the muon spin relaxation rate increases with decreasing temperature and then levels off below around 10 K, which is reminiscent of the frustrated systems. An enhancement of the relaxation rate by a longitudinal field in the paramagnetic state is observed for NTO and eliminated by a magnetic dilution for the NLTO sample. This suggests that the spectral density is modified by a magnetic dilution and thus indicates that the spins behave cooperatively rather than individually. The zero-field measurement at 0.3 K indicates that the magnetic ground state for NTO is ferromagnetic.
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Affiliation(s)
- Hanjie Guo
- Department of Physics and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, People's Republic of China
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Yaouanc A, Dalmas de Réotier P, Bonville P, Hodges JA, Glazkov V, Keller L, Sikolenko V, Bartkowiak M, Amato A, Baines C, King PJC, Gubbens PCM, Forget A. Dynamical splayed ferromagnetic ground state in the quantum spin ice Yb(2)Sn(2)O(7). PHYSICAL REVIEW LETTERS 2013; 110:127207. [PMID: 25166842 DOI: 10.1103/physrevlett.110.127207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/24/2013] [Indexed: 06/03/2023]
Abstract
From magnetic, specific heat, (170)Yb Mössbauer effect, neutron diffraction, and muon spin relaxation measurements on polycrystalline Yb(2)Sn(2)O(7), we show that below the first order transition at 0.15 K all of the Yb(3+) ions are long-range magnetically ordered and each has a moment of 1.1 μ(B) which lies at ≃ 10° to a common fourfold cubic axis. The four sublattice moments have four different directions away from this axis and are therefore noncoplanar. We term this arrangement splayed ferromagnetism. This ground state has a dynamical component with a fluctuation rate in the megahertz range. The net ferromagnetic exchange interaction has an anisotropy that favors the local threefold axis. We discuss our results in terms of the phase diagram proposed by Savary and Balents [Phys. Rev. Lett. 108, 037202 (2012)] for a pyrochlore lattice of Kramers 1/2 effective spins.
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Affiliation(s)
- A Yaouanc
- Institut Nanosciences et Cryogénie, SPSMS, CEA and Université Joseph Fourier, F-38054 Grenoble, France
| | - P Dalmas de Réotier
- Institut Nanosciences et Cryogénie, SPSMS, CEA and Université Joseph Fourier, F-38054 Grenoble, France
| | - P Bonville
- CEA/DSM, Institut Rayonnement Matière de Saclay, SPEC, 91191 Gif-sur-Yvette, France
| | - J A Hodges
- CEA/DSM, Institut Rayonnement Matière de Saclay, SPEC, 91191 Gif-sur-Yvette, France
| | - V Glazkov
- Institut Nanosciences et Cryogénie, SPSMS, CEA and Université Joseph Fourier, F-38054 Grenoble, France and P.L. Kapitza Institute for Physical Problems, RAS, 119334 Moscow, Russia
| | - L Keller
- Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - V Sikolenko
- Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - M Bartkowiak
- Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - A Amato
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - C Baines
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - P J C King
- Rutherford Appleton Laboratory, ISIS Facility, Chilton OX11 0QX, United Kingdom
| | - P C M Gubbens
- FAME, R3, Applied Sciences, Delft University of Technology, 2629JB Delft, The Netherlands
| | - A Forget
- CEA/DSM, Institut Rayonnement Matière de Saclay, SPEC, 91191 Gif-sur-Yvette, France
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8
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Pregelj M, Zorko A, Zaharko O, Arčon D, Komelj M, Hillier AD, Berger H. Persistent spin dynamics intrinsic to amplitude-modulated long-range magnetic order. PHYSICAL REVIEW LETTERS 2012; 109:227202. [PMID: 23368156 DOI: 10.1103/physrevlett.109.227202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Indexed: 06/01/2023]
Abstract
An incommensurate elliptical helical magnetic structure in the frustrated coupled-spin-chain system FeTe(2)O(5)Br is surprisingly found to persist down to 53(3) mK (T/T(N)~1/200), according to neutron scattering and muon spin relaxation. In this state, finite spin fluctuations at T→0 are evidenced by muon depolarization, which is in agreement with specific-heat data indicating the presence of both gapless and gapped excitations. We thus show that the amplitude-modulated magnetic order intrinsically accommodates contradictory persistent spin dynamics and long-range order and can serve as a model structure to investigate their coexistence.
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Affiliation(s)
- M Pregelj
- Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
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9
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Hodges JA, Dalmas de Réotier P, Yaouanc A, Gubbens PCM, King PJC, Baines C. Magnetic frustration in the disordered pyrochlore Yb(2)GaSbO(7). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:164217. [PMID: 21471632 DOI: 10.1088/0953-8984/23/16/164217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In the pyrochlore Yb(2)GaSbO(7), the Yb(3+) sublattice forms a network of corner sharing tetrahedra and the second sublattice is made up of disordered, non-magnetic Ga(3+) and Sb(5+) ions. We have examined this compound using magnetic susceptibility, (170)Yb Mössbauer spectroscopy (down to 0.03 K) and muon spin relaxation (μSR) (down to 0.02 K) measurements. We establish the size of the Yb(3+) magnetic moments and that of the Yb(3+)-Yb(3+) coupling. At low temperatures, the correlated moments fluctuate between directions that are well tilted relative to the local [111] axis. The lattice disorder does not quench the frustration induced low temperature spin fluctuations but it does remove the first order dynamic transition that is present in the crystallographically ordered counterpart Yb(2)Ti(2)O(7). Below 1.0 K, the fluctuation rate of the correlated moments decreases progressively as the temperature is reduced and the moments remain dynamic down to 0.02 K where the rate is 7 × 10(7) s(-1). Magnetic frustration is operative in Yb(2)GaSbO(7) where the Yb(3+)-Yb(3+) interaction is antiferromagnetic as it is in Yb(2)Ti(2)O(7) where the interaction is ferromagnetic.
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Affiliation(s)
- J A Hodges
- CEA-Saclay, IRAMIS/SPEC, F-91191 Gif sur Yvette, France
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10
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McClarty PA, Cosman JN, Del Maestro AG, Gingras MJP. Calculation of the expected zero-field muon relaxation rate in the geometrically frustrated rare earth pyrochlore Gd(2)Sn(2)O(7) antiferromagnet. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:164216. [PMID: 21471617 DOI: 10.1088/0953-8984/23/16/164216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The magnetic insulator Gd(2)Sn(2)O(7) is one of many geometrically frustrated magnetic materials known to exhibit a nonzero muon spin polarization relaxation rate, λ(T), down to the lowest temperature (T) studied. Such behaviour is typically interpreted as signalling the presence of persistent spin dynamics (PSD) of the host material. In the case of Gd(2)Sn(2)O(7), such PSD comes as a surprise since magnetic specific heat measurements suggest conventional gapped magnons, which would naively lead to an exponentially vanishing λ(T) as T → 0. In contrast to most materials that display PSD, the ordered phase of Gd(2)Sn(2)O(7) is well characterized and both the nature and the magnitude of the interactions have been inferred from the magnetic structure and the temperature dependence of the magnetic specific heat. Based on this understanding, the temperature dependence of the muon spin polarization relaxation through the scattering of spin waves (magnons) is calculated. The result explicitly shows that, despite the unusual extensive number of weakly dispersive (gapped) excitations characterizing Gd(2)Sn(2)O(7), a remnant of the zero modes of the parent frustrated pyrochlore Heisenberg antiferromagnet, the temperature dependence of the calculated λ(T) differs dramatically from the experimental one. Indeed, the calculation conforms to the naive expectation of an exponential collapse of λ(T) at temperatures below ∼ 0.7 K. This result, for the first time, illustrates crisply and quantitatively the paradox that presents itself with the pervasive occurrence of PSD in highly frustrated magnetic systems as evinced by muon spin relaxation measurements.
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Affiliation(s)
- P A McClarty
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
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13
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Cao HB, Gukasov A, Mirebeau I, Bonville P. Anisotropic exchange in frustrated pyrochlore Yb(2)Ti(2)O(7). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:492202. [PMID: 21836187 DOI: 10.1088/0953-8984/21/49/492202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The local Yb(3+) magnetic susceptibility tensor was recently measured in the frustrated pyrochlore compound Yb(2)Ti(2)O(7) by means of in-field polarized neutron scattering in a single crystal. A very anisotropic effective exchange tensor was derived for the Yb(3+) ion. Using this result, we reinterpret here the data for the powder susceptibility in Yb(2)Ti(2)O(7). We show that, in the case of a well-isolated Kramers doublet with anisotropic g and exchange tensors, the inverse susceptibility for a powder sample does not strictly obey a Curie-Weiss law at low temperature. We discuss the consequences regarding the paramagnetic Curie temperature, usually taken as a measure of the exchange/dipolar interaction, and the exotic 'slow fluctuation' ground state of Yb(2)Ti(2)O(7).
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Affiliation(s)
- H B Cao
- CEA, Centre de Saclay, Laboratoire Léon Brillouin, F-91191 Gif-sur-Yvette, France
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14
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Rule KC, Ehlers G, Gardner JS, Qiu Y, Moskvin E, Kiefer K, Gerischer S. Neutron scattering investigations of the partially ordered pyrochlore Tb(2)Sn(2)O(7). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:486005. [PMID: 21832537 DOI: 10.1088/0953-8984/21/48/486005] [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
Neutron scattering measurements have been performed on polycrystalline Tb(2)Sn(2)O(7) at temperatures above and below that of the phase transition, T(N) = 0.87 K, to investigate further the spin dynamics in the magnetically ordered state. In particular, new neutron spin echo results are presented showing a dependence on Q in the dynamics. We show evidence of the coexistence of static ferromagnetism and dynamically fluctuating spins down to 30 mK and we make a comparison of this partially ordered system to the spin liquid Tb(2)Ti(2)O(7).
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Affiliation(s)
- K C Rule
- Helmholtz Zentrum Berlin, 14109 Berlin, Germany
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15
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Giblin SR, Champion JDM, Zhou HD, Wiebe CR, Gardner JS, Terry I, Calder S, Fennell T, Bramwell ST. Static magnetic order in Tb2Sn2O7 revealed by muon spin relaxation with exterior muon implantation. PHYSICAL REVIEW LETTERS 2008; 101:237201. [PMID: 19113586 DOI: 10.1103/physrevlett.101.237201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 10/16/2008] [Indexed: 05/27/2023]
Abstract
Tb2Sn2O7 has been proposed as an ordered spin ice, but the precise nature of the low temperature magnetic state remains uncertain. Recent independent muon spin relaxation (microSR) investigations suggest the possibility of exotic ground states with static order precluded on time scales longer than 10(-6) s. Here the more conventional hypothesis of canted ferromagnetism is tested by means of microSR with the muons stopped outside the sample, as well as ultralow field bulk magnetization measurements. The field cooled state shows conventional static order, while the zero field cooled state may be interpreted in terms of conventional closed domains. These results rule out purely dynamical ground states and illustrate the value of exterior muon implantation as a complement to the conventional technique.
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Affiliation(s)
- S R Giblin
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, United Kingdom.
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Lancaster T, Blundell SJ, Andreica D, Janoschek M, Roessli B, Gvasaliya SN, Conder K, Pomjakushina E, Brooks ML, Baker PJ, Prabhakaran D, Hayes W, Pratt FL. Magnetism in geometrically frustrated YMnO3 under hydrostatic pressure studied with muon spin relaxation. PHYSICAL REVIEW LETTERS 2007; 98:197203. [PMID: 17677657 DOI: 10.1103/physrevlett.98.197203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Indexed: 05/16/2023]
Abstract
The ferroelectromagnet YMnO3 consists of weakly coupled triangular layers of S=2 spins. Below T(N) approximately equal to 70 K muon-spin relaxation data show two oscillatory relaxing signals due to magnetic order, with no purely relaxing signals resolvable (which would require different coexisting spin distributions). The transition temperature T(N) increases with applied hydrostatic pressure, even though the ordered moment decreases. These results suggest that pressure increases both the exchange coupling between the layers and the frustration within the layers.
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Affiliation(s)
- T Lancaster
- Clarendon Laboratory, Department of Physics, Oxford University, Parks Road, Oxford, OX1 3PU, United Kingdom.
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