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.
@article{arxiv.1109.3090,
title = {Prediction of the Magnetotoroidic Effect from Atomistic Simulations},
author = {Wei Ren and L. Bellaiche},
journal= {arXiv preprint arXiv:1109.3090},
year = {2011}
}