First Principles Investigation of Ferromagnetism and Ferroelectricity in Bismuth Manganite

TL;DR

This study uses first-principles calculations to explore the origins of ferromagnetism and ferroelectricity in bismuth manganite, revealing covalent bonding's role in stabilizing unique magnetic and structural phases.

Contribution

It provides a detailed first-principles analysis of bismuth manganite's magnetic and structural properties, highlighting the role of covalent bonding, which was not previously understood.

Findings

Covalent bonding between bismuth and oxygen stabilizes unique phases.

Differences from other perovskite manganites are due to bonding interactions.

Results align with experimental observations of charge ordering enhancement.

Abstract

We present results of local spin density approximation (LSDA) pseudopotential calculations for the perovskite structure oxide, bismuth manganite (BiMnO3). The origin of the differences between bismuth manganite and other perovskite manganites is determined by first calculating total energies and band structures of the high symmetry cubic phase, then sequentially lowering the magnetic and structural symmetry. Our results indicate that covalent bonding between bismuth cations and oxygen anions stabilizes different magnetic and structural phases compared with the rare earth manganites. This is consistent with recent experimental results showing enhancement of charge ordering in doped bismuth manganite.