Non-magnetic ion site disorder effects on the quantum magnetism of a spin-1/2 equilateral triangular lattice antiferromagnet
- Univ. of Tennessee, Knoxville, TN (United States)
- Rutgers Univ., Piscataway, NJ (United States)
- Florida State Univ., Tallahassee, FL (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Manitoba, Winnipeg, MB (Canada)
- Univ. of Manitoba, Winnipeg (Canada); Univ. of Winnipeg, Manitoba (Canada)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Shanghai Jiao Tong Univ. (China); Chinese Academy of Sciences (CAS), Shenyang (China)
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
- Univ. of Tennessee, Knoxville, TN (United States); Florida State Univ., Tallahassee, FL (United States)
Here, with the motivation to study how non-magnetic ion site disorder affects the quantum magnetism of Ba3CoSb2O9, a spin-1/2 equilateral triangular lattice antiferromagnet, we performed DC and AC susceptibility, specific heat, elastic and inelastic neutron scattering measurements on single crystalline samples of Ba2.87Sr0.13CoSb2O9 with Sr doping on non-magnetic Ba2+ ion sites. The results show that Ba2.87Sr0.13CoSb2O9 exhibits (i) a two-step magnetic transition at 2.7 K and 3.3 K, respectively; (ii) a possible canted 120 degree spin structure at zero field with reduced ordered moment as 1.24 μB/Co; (iii) a series of spin state transitions for both H∥ab-plane and H∥c-axis. For H∥ab-plane, the magnetization plateau feature related to the up–up–down phase is significantly suppressed; (iv) an inelastic neutron scattering spectrum with only one gapped mode at zero field, which splits to one gapless and one gapped mode at 9 T. All these features are distinctly different from those observed for the parent compound Ba3CoSb2O9, which demonstrates that the non-magnetic ion site disorder (the Sr doping) plays a complex role on the magnetic properties beyond the conventionally expected randomization of the exchange interactions. We propose the additional effects including the enhancement of quantum spin fluctuations and introduction of a possible spatial anisotropy through the local structural distortions.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); National Science and Engineering Research Council (NSERC); Canadian Foundation for Innovation (CFI); Beckman Young Investigator Award; National Science Foundation of China
- Grant/Contract Number:
- AC05-00OR22725; DMR-2003117; DMR-1157490; DMR-1508249; 11774223; U2032213
- OSTI ID:
- 1872842
- Journal Information:
- Journal of Physics. Condensed Matter, Vol. 34, Issue 20; ISSN 0953-8984
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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