Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102142
Title: Spin glass behavior in frustrated quantum spin system CuAl2O4 with a possible orbital liquid state
Authors: Nirmala, R.
Jang, K. -H.
Sim, H.
Cho, H.
Lee, J.
Yang, N. -G.
Lee, S.
Ibberson, R. M.
Kakurai, K.
Matsuda, M.
Cheong, S. -W.
Gapontsev, V. V.
Streltsov, S. V.
Park, J. -G.
Issue Date: 2017
Publisher: Institute of Physics Publishing
Citation: Spin glass behavior in frustrated quantum spin system CuAl2O4 with a possible orbital liquid state / R. Nirmala, K. -H. Jang, H. Sim, et al. — DOI 10.1088/1361-648X/aa5c72 // Journal of Physics Condensed Matter. — 2017. — Vol. 29. — Iss. 13. — 13LT01.
Abstract: CuAl2O4 is a normal spinel oxide having quantum spin, S = 1/2 for Cu2+. It is a rather unique feature that the Cu2+ ions of CuAl2O4 sit at a tetrahedral position, not like the usual octahedral position for many oxides. At low temperatures, it exhibits all the thermodynamic evidence of a quantum spin glass. For example, the polycrystalline CuAl2O4 shows a cusp centered at ∼2 K in the low-field dc magnetization data and a clear frequency dependence in the ac magnetic susceptibility while it displays logarithmic relaxation behavior in a time dependence of the magnetization. At the same time, there is a peak at ∼2.3 K in the heat capacity, which shifts towards a higher temperature with magnetic fields. On the other hand, there is no evidence of new superlattice peaks in the high-resolution neutron powder diffraction data when cooled from 40 to 0.4 K. This implies that there is no long-ranged magnetic order down to 0.4 K, thus confirming a spin glass-like ground state for CuAl2O4. Interestingly, there is no sign of structural distortion either although Cu2+ is a Jahn-Teller active ion. Thus, we claim that an orbital liquid state is the most likely ground state in CuAl2O4. Of further interest, it also exhibits a large frustration parameter, f = |θ CW/T m| ∼ 67, one of the largest values reported for spinel oxides. Our observations suggest that CuAl2O4 should be a rare example of a frustrated quantum spin glass with a good candidate for an orbital liquid state. © 2017 IOP Publishing Ltd.
Keywords: FRUSTRATION
ORBITAL LIQUID STATE
QUANTUM SPIN SYSTEM
SPIN GLASS
GLASS
GROUND STATE
LANTHANUM COMPOUNDS
LIQUIDS
MAGNETIC SUSCEPTIBILITY
MAGNETISM
MAGNETIZATION
SPECIFIC HEAT
SPIN DYNAMICS
SPIN GLASS
AC MAGNETIC SUSCEPTIBILITY
FRUSTRATION
HIGH RESOLUTION NEUTRON POWDER DIFFRACTION DATA
LOGARITHMIC RELAXATION
ORBITAL LIQUID
QUANTUM SPIN SYSTEMS
STRUCTURAL DISTORTIONS
TETRAHEDRAL POSITION
QUANTUM THEORY
URI: http://hdl.handle.net/10995/102142
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85015229087
PURE ID: 1689606
6381f275-7561-45e8-a8e8-6cd335baccc6
ISSN: 9538984
DOI: 10.1088/1361-648X/aa5c72
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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