Multiferroic behavior of Aurivillius Bi4Mn3O12 from first-principles

TL;DR

This study uses first-principles calculations to explore the multiferroic properties of the hypothetical Bi4Mn3O12 compound, revealing its magnetic and ferroelectric tendencies and how they can be influenced by strain or substitution.

Contribution

It provides the first theoretical investigation of Bi4Mn3O12's multiferroic behavior, highlighting the effects of Mn ions on its structural and electronic properties.

Findings

Bi4Mn3O12 is ferromagnetic in the tetragonal paraelectric phase.

Antiferrodistortive instability dominates over ferroelectricity at equilibrium volume.

Strain or Mn-to-Ti substitution can promote ferroelectricity.

Abstract

The multiferroic behavior of the hypothetical Aurivillius compound Bi4Mn3O12 has been explored on the basis of density functional calculations. We find that the tetragonal paraelectric phase of this material is ferromagnetic, showing ferroelectric and antiferrodistortive instabilities similar to the ones observed in its ferroelectric parent compound Bi4Ti3O12 . Our results indicate, however, that the presence of Mn+4 ions at the B-sites shrinks the cell volume and consequently the unstable polar mode, associated with the ferroelectric polarization, is overcame by an antiferrodistortive distortion. In this way, Bi4Mn3O12 exhibits incipient ferroelectricity at its equilibrium volume. We show that the ferroelectric state can be favored by strain or partial substitution of Mn with Ti.