Magnetic configurations in cubic Bi2MnFeO6 alloys from first-principles

TL;DR

This study uses first-principles calculations to explore the magnetic configurations and properties of cubic Bi2MnFeO6 alloys, including the effects of atomic distribution and lattice contraction, revealing robust magnetic moments and the mediating role of oxygen.

Contribution

It extends previous work on BiFeO3 alloys by analyzing Bi2MnFeO6 with various atomic arrangements and magnetic states using first-principles methods.

Findings

Fe and Mn atoms have magnetic moments exceeding 3 μ_B

Magnetic properties are similar to parent BiMnO3 and BiFeO3 compounds

Oxygen mediates magnetic interactions and screens environmental changes

Abstract

We expand our study on cubic BiFeO$_3$ alloys presented in [K. Koumpouras and I. Galanakis, \textit{J. Magn. Magn. Mater} 323, 2328 (2011)] to include also the BiMnO$_3$ and Bi$_2$MnFeO$_6$ alloys. For the latter we considered three different cases of distribution of the Fe-Mn atoms in the lattice and six possible magnetic configurations. We show that Fe and Mn atoms in all cases under study retain a large spin magnetic moment, the magnitude of which exceeds the 3 $\mu_B$. Their electronic and magnetic properties are similar to the ones in the parent BiMnO$_3$ and BiFeO$_3$ compounds. Thus oxygen atoms which are the nearest-neighbors of Fe(Mn) atoms play a crucial role since they mediate the magnetic interactions between the transition metal atoms and screen any change in their environment. Finally, we study the effect of lattice contraction on the magnetic properties of Bi$_2$MnFeO$_6$.