Journal Article

Spin-orbit coupling control of anisotropy, ground state and frustration in 5d2 Sr2MgOsO6

Taylor, Alice E., Büchner, Bernd, Woodward, Patrick M., Xiong, Jie, Wolter, A. U. B., Christianson, A. D., Wurmehl, Sabine, Aczel, Adam A., Kolesnikov, A. I., Singh, D. J., Rodan, Steven, Stone, M. B., Morrow, Ryan

2016

Overview

The influence of spin-orbit coupling (SOC) on the physical properties of the 5 d 2 system Sr 2 MgOsO 6 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 Sr 2 MgOsO 6 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 5 d 2 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 size of the local moment in this compound. Through comparison to Sr 2 ScOsO 6 , it is demonstrated that SOC-induced anisotropy has the ability to relieve frustration in 5 d 2 systems relative to their 5 d 3 counterparts, providing an explanation of the high T N found in Sr 2 MgOsO 6 .

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 639/638/263 / 639/638/263/915 / 639/638/298/920 / 639/766/119 / 639/766/119/997 / Anisotropy / High temperature / Humanities and Social Sciences / multidisciplinary / Neutron scattering / Neutrons / Physical properties / Science / solar (photovoltaic), solar (thermal), solid state lighting, phonons, thermal conductivity, thermoelectric, defects, mechanical behavior, charge transport, spin dynamics, materials and chemistry by design, optics, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing) / Specific heat / Temperature effects