Novel magnetoelectric effects via penta-linear interactions

TL;DR

This paper introduces high-order penta-linear couplings in magnetoelectric perovskite films, enabling electric-field control and switching of magnetization, which could lead to advanced spintronic and magnonic devices.

Contribution

It reports the discovery of novel penta-linear magnetoelectric couplings using first-principles and phenomenological theories, expanding the understanding of electric control over magnetization.

Findings

Electric-field control of magnetization magnitude and sign

Discrete switching of magnetization magnitude

Potential for new spintronic and magnonic device applications

Abstract

Magnetoelectric multiferroic materials, particularly with the perovskite structure, are receiving a lot of attention because of their inherent coupling between electrical polarization and magnetic ordering. However, very few types of direct coupling between polarization and magnetization are known, and it is unclear whether they can be useful to the design of novel spintronic devices exploiting the control of magnetization by electric fields. For instance, the typical bi-quadratic coupling only allows to change the magnitude of the magnetization by an electric field, but it does not permit an electric-field-induced switching of the magnetization. Similarly, the so-called Lifshitz invariants allow an electric-field control of complicated magnetic orderings, but not of the magnetization. Here, we report the discovery of novel direct couplings between polarization and magnetization in epitaxial perovskite films, via the use of first-principles methods and the development of an original Landau-type phenomenological theory. Our results feature penta-linear interactions involving the ferromagnetic and anti-ferromagnetic vectors as well as the polar distortions and oxygen octahedral tilting, and permit a number of striking effects. Examples include a continuous electric-field control of the magnetization magnitude and sign, and the discrete switching of the magnetization magnitude. Thus, the high-order, penta-linear couplings demonstrated in this work may open new paths towards novel magneto-electric effects, as well as, spintronic and magnonic devices.