Space-Time Parity Violation and Magnetoelectric Interactions in Antiferromagnets

TL;DR

This paper explores the unique properties of antiferromagnets with broken space-time parity, focusing on BiFeO3, revealing unusual effects like modulated spin structures and coexistence of magnetoelectric phenomena.

Contribution

It provides a detailed analysis of how broken parity in antiferromagnets leads to novel effects such as linear magnetoelectricity and toroidal moments, especially in BiFeO3.

Findings

Presence of spatially modulated spin structures in BiFeO3

Coexistence of linear magnetoelectric effect with weak ferromagnetism

Magnetic-induced phase transitions with unusual effects

Abstract

The properties of antiferromagnetic materials with violated space-time parity are considered. Particular attention is given to the bismuth ferrite BiFeO3 ferroelectric magnet. This material is distinguished from other antiferromagnets in that the inversion center is absent in its crystal and magnetic structures. This circumstance gives rise to the diversified and unusual properties, namely, to the appearance of a spatially modulated spin structure and to the unique possibility of the linear magnetoelectric effect coexisting with a weak ferromagnetic moment. The magnetic-induced phase transitions accompanied by the suppression of the modulated spin structure and appearance of a number of new and unusual effects are considered. These are the linear magnetoelectric effect and the appearance of a toroidal moment and a weak ferromagnetic moment of the magnetoelectric nature.