Prediction of the Magnetotoroidic Effect from Atomistic Simulations

TL;DR

This paper uses atomistic simulations to demonstrate how curled electric fields can control magnetization in BiFeO3 nanostructures through a novel magnetotoroidic effect involving vortex transformations.

Contribution

It introduces a new atomistic simulation approach to predict the magnetotoroidic effect driven by electric vortex switching in ferroelectric materials.

Findings

Electric fields can control magnetization magnitude and direction.

Magnetotoroidic effect involves vortex transformations and couplings.

Intermediate states are key to the control mechanism.

Abstract

An effective Hamiltonian technique is used to investigate the effect of applying curled electric fields on physical properties of stress-free BiFeO3 dots being under open-circuit electrical boundary conditions. It is discovered that such fields can lead to a control of not only the magnitude but also the direction of the magnetization. On a microscopic point of view, such control originates from the field-induced transformation or switching of electrical vortices and their couplings with oxygen octahedral tilts and magnetic dipoles. This control involves striking intermediate states, and constitutes a novel phenomenon that can be termed as "magnetotoroidic" effect.