Magnetism in Cation-Ordered Multicomponent Oxide Perovskites

Cation ordering of A and B sites in ABO(3) perovskite-derived multicomponent structures can give rise to fascinating properties. Following this, in recent times, high-pressure synthesis of double double perovskites and quadruple perovskites have been reported, incorporating transition metal ions at the A site along with alkali metal/alkaline earth or rare earth A cations. This is expected to further improve the magnetic properties of B-site-ordered double perovskites. In this study, we consider three Fe-Re-based multicomponent compounds: CaCuFeReO6, CaMnFeReO6, and CaCu3Fe2Re2O12. While the first two compounds belong to the class of double double perovskite with 1:1 cation ordering at the A site, the third compound belongs to the class of quadruple perovskite with 1:3 cation-ordered A sites. Despite the chemical diversity as well as structural diversity of the magnetic A site in the three compounds, their high-temperature magnetic behavior is found to be similar, posing a puzzle. In our computational study, we unravel the underlying mechanism of magnetism, thus demystifying the situation. We also provide a theoretical description of the observed magneto-resistive behavior of CaCuFeReO6 and CaCu3Fe2Re2O12.