Spin glass behavior in frustrated quantum spin system CuAl 2 O 4 with a possible orbital liquid state
- Seoul National Univ. (Korea, Republic of). Center for Stronly Correlated Materials Research; Indian Inst. of Technology (IIT), Madras (India). Dept. of Physics; Sungkyunkwan Univ., Suwon (Republic of Korea). Dept. of Physics
- Seoul National Univ. (Korea, Republic of). Center for Stronly Correlated Materials Research; Sungkyunkwan Univ., Suwon (Republic of Korea). Dept. of Physics
- Inst. for Basic Science, Seoul (Korea, Republic of). Center for Correlated Electron Systems; Seoul National Univ. (Korea, Republic of). Dept. of Physics and Astronomy
- Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of). Neturon Science Division; Rutgers Univ., Piscataway, NJ (United States). Rutgers Center for Emergent Materials and Dept. of Physics and Astronomy
- ISIS Facility, Didcot (United Kingdom). Rutherford Appleton Lab.; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials
- Japan Atomic Energy Agency (JAEA), Tokai (Japan). Quantum Beam Science Center
- Japan Atomic Energy Agency (JAEA), Tokai (Japan). Quantum Beam Science Center; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
- Rutgers Univ., Piscataway, NJ (United States). Rutgers Center for Emergent Materials and Dept. of Physics and Astronomy
- Russian Academy of Sciences (RAS), Ekaterinburg (Russian Federation). MN Miheev Inst. of Metal Physics of Ural Branch
- Russian Academy of Sciences (RAS), Ekaterinburg (Russian Federation). MN Miheev Inst. of Metal Physics of Ural Branch; Ural Federal Univ., Ekaterinburg (Russia)
- Seoul National Univ. (Korea, Republic of). Center for Stronly Correlated Materials Research; Sungkyunkwan Univ., Suwon (Republic of Korea). Dept. of Physics; Inst. for Basic Science, Seoul (Korea, Republic of). Center for Correlated Electron Systems; Seoul National Univ. (Korea, Republic of). Dept. of Physics and Astronomy
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. Conversely, 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. Therefore, 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. These observations suggest that CuAl2O4 should be a rare example of a frustrated quantum spin glass with a good candidate for an orbital liquid state.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-00OR22725; FG02-07ER46382
- OSTI ID:
- 1346686
- Journal Information:
- Journal of Physics. Condensed Matter, Journal Name: Journal of Physics. Condensed Matter Journal Issue: 13 Vol. 29; ISSN 0953-8984
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Theoretical evidence of spin-orbital-entangled J eff = 1 2 state in the 3 d transition metal oxide CuAl 2 O 4
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journal | October 2019 |
Field-cooling induced giant vertical magnetization shift in frustrated low dimensional spin-chain Sr 3 NiIrO 6 system
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journal | August 2019 |
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