The electronic ground state of ${\mathrm{Ca}}_3{\mathrm{LiOsO}}_6$ was recently considered within an intermediate coupling regime that revealed $J=3/2$ spin-orbit entangled magnetic moments. Through inelastic neutron scattering and density functional theory we investigate the magnetic interactions and probe how the magnetism is influenced by the change in hierarchy of interactions as we move from ${\mathrm{Ca}}_3{\mathrm{LiOsO}}_6$ ($5d^3$) to ${\mathrm{Ca}}_3{\mathrm{LiRuO}}_6$ ($4d^3$). An alteration of the spin gap and ordered local moment is observed, however the magnetic structure, Néel temperature, and exchange interactions are unaltered. To explain this behavior it is necessary to include both spin-orbit coupling and hybridization, indicating the importance of an intermediate coupling approach when describing $5d$ oxides.

• Received 8 September 2017
• Revised 6 November 2017

DOI:https://doi.org/10.1103/PhysRevB.96.184426