Spin-orbit coupling control of anisotropy, ground state and frustration in 5d₂Sr₂MgOsO₆

Journal Article · Mon Aug 29 20:00:00 EDT 2016 · Scientific Reports

DOI: https://doi.org/10.1038/srep32462 · OSTI ID:1319201

Morrow, Ryan ^[1]; Taylor, Alice E. ^[2]; Singh, D. J. ^[3]; Xiong, Jie ^[1]; Rodan, Steven ^[4]; Wolter, A. U. B. ^[4]; Wurmehl, Sabine ^[5]; Büchner, Bernd ^[5]; Stone, M. B. ^[2]; Kolesnikov, A. I. ^[2]; Aczel, Adam A. ^[2]; Christianson, A. D. ^[6]; Woodward, Patrick M. ^[1]

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1. The Ohio State Univ., Columbus, OH (United States). Dept of Chemistry and Biochemistry
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
3. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
4. Leibniz Inst. for Solid State and Materials Research (IFW), Dresden (Germany)
5. Leibniz Inst. for Solid State and Materials Research (IFW), Dresden (Germany); Dresden Univ. of Technology (Germany). Inst. for Solid State Physics
6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy

The influence of spin-orbit coupling (SOC) on the physical properties of the 5d² system Sr₂MgOsO₆ is probed via a combination of magnetometry, specific heat measurements, elastic and inelastic neutron scattering, and density functional theory calculations. Although a significant degree of frustration is expected, we find that Sr₂MgOsO₆ orders in a type I antiferromagnetic structure at the remarkably high temperature of 108 K. The measurements presented allow for the first accurate quantification of the size of the magnetic moment in a 5d² system of 0.60(2) μ_B a significantly reduced moment from the expected value for such a system. Furthermore, significant anisotropy is identified via a spin excitation gap, and we confirm by first principles calculations that SOC not only provides the magnetocrystalline anisotropy, but also plays a crucial role in determining both the ground state magnetic order and the moment size in this compound. In conclusion, through comparison to Sr₂ScOsO₆, it is demonstrated that SOC-induced anisotropy has the ability to relieve frustration in 5d² systems relative to their 5d³ counterparts, providing an explanation of the high TN found in Sr₂MgOsO₆.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Spallation Neutron Source
• Sponsoring Organization: Deutsche Forschungsgemeinschaft DFG; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC05-00OR22725; SC0001299
• OSTI ID: 1319201
• Journal Information: Scientific Reports, Journal Name: Scientific Reports Vol. 6; ISSN 2045-2322
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English