First-principles screening of ABO3 oxides with two magnetic sublattices

Work on orthoferrite perovskites (e.g., ${\mathrm{GdFeO}}₃$) shows that $\mathit{AB}{\mathrm{O}}₃$ oxides with $A$ and $B$ magnetic cations present novel behaviors (e.g., magnetoelectric) not possible when only one cation has spin. Unfortunately, the magnetic $A$ cations are usually lanthanides whose $4f$ electrons interact weakly, restricting the most interesting effects to low temperatures. Here we explore the possibility of having both $A$ and $B$ sites occupied by $3d$ transition metals, by running a systematic first-principles investigation of 81 compositions, considering the polymorphs most likely to be stable in bulk or thin-film forms (perovskite, corundum derivatives). We predict specific compounds to be multiferroics at high temperature, multiferroics with large magnetic moments, ``multiferroic metals'' (i.e., as the much-sought ``polar metals,'' but also magnetic), and ferromagnetic insulators. Our results offer a compelling panoramic of these compounds and the possibilities they offer, providing plenty of directions for further original research, both theoretical and experimental.