Predicted polymorph manipulation in an exotic double perovskite oxide

Abstract

Predicted polymorph manipulation offers a cutting-edge route to design function-oriented materials in an exotic double perovskite-related oxide A₂BB′O₆ with small A-site cations. Herein, first-principles density functional theory calculations in light of the equation of state for solid, for the first time, was used to predict the Mg₃TeO₆ (R)-to-perovskite (P2₁/n) type phase transition in Mn₃TeO₆ at around 5 GPa, regardless of the deployment of magnetic interactions. The high-pressure synthesis and synchrotron diffraction crystal structure analysis corroborated experimentally the polymorph variation in Mn₂²⁺Mn²⁺Te⁶⁺O₆, which was accompanied by a 13 K increase in the antiferromagnetic ordering temperature (37 K) in the high-pressure perovskite polymorph compared to that of the ambient-pressure R phase (24 K). The magnetodielectric coupling remains up to 50 K with the maximum being around the magnetic ordering temperature in the perovskite Mn₃TeO₆. Thus, the predicted polymorph manipulation here offers the possibility of discovering accelerated materials by inverse design in exotic perovskite oxides.