A cluster calculation investigation of the A- and B-sites ordered perovskite oxide CaCu₃Fe₂Os₂O₁₂

Abstract Taking the quadruple perovskite oxide CaCu 3 Fe 2 Os 2 O 12 as an example, by performing both experimental sum rules and theoretical configuration interaction cluster calculations, we have investigated the spin and orbital configurations of all the transition metal cations, Cu, Fe and Os, as well as their local microscopic physical parameters of crystal field, spin-orbit coupling (SOC), Coulomb potential and hybridization. Specially, we found that the Os 5+ (5 d 3 ) with a half-filled t 2g orbital exhibits a large orbital moment on account of the mixing of t2g and eg orbitals, which can be ascribed to the strong SOC of the 5d elements. On the other hand, SOC of the Cu 2+ (3 d 9 ) is markedly reduced, but is still nonnegligible compared to the crystal field 10 Dq , leading to a finite orbital moment of Cu 2+ . This work provides a microscopic and element-selective perspective of the local environment of the magnetic cations in complex compounds.