Exchange interaction in ACu3Fe2Re2O12 quadruple perovskites

TL;DR

This paper uses first-principles calculations to analyze the electronic structure and magnetic interactions in ACu3Fe2Re2O12 quadruple perovskites, explaining their high Curie temperatures and magnetic properties.

Contribution

It introduces a band mechanism model for magnetism in these perovskites and links magnetic exchange interactions to Re t2g state filling, aligning theoretical Curie temperatures with experiments.

Findings

Antiferromagnetic exchange interactions depend on Re t2g filling.

Ferrimagnetic ground state stabilized by antiferromagnetic interactions.

Calculated Curie temperatures agree with experimental data.

Abstract

Quadruple perovskites ACu$_3$Fe$_2$Re$_2$O$_{12}$ attract considerable interest due to their high Curie temperatures (up to $710$K), which strongly depend on the A-site cation. In this work, we employ first-principles calculations to investigate their electronic structure and magnetic exchange interactions. A band mechanism of magnetism that explains the antiferromagnetic character of the exchange interactions and their strong dependence on the filling of the Re $t_{2g}$ states is proposed. These antiferromagnetic interactions stabilize ferrimagnetic ground state. The calculated Curie temperatures, obtained within the Onsager reaction field theory, are in a good agreement with experimental data.