Reversible Control of Magnetic Interactions by Electric Field in a Single Phase Material

TL;DR

This paper demonstrates that applying an electric field to a strained EuTiO3 film can reversibly switch its magnetic ground state, revealing a strong magnetoelectric coupling with potential device applications.

Contribution

It shows how strain and electric fields can control magnetic interactions in a single phase EuTiO3 film, revealing a giant magnetoelectric effect with a microscopic understanding.

Findings

Electric field switches magnetic ground state in EuTiO3

Strain enhances magnetoelectric coupling

First-principles calculations explain the microscopic mechanism

Abstract

Intrinsic magnetoelectric coupling describes the interaction between magnetic and electric polarization through an inherent microscopic mechanism in a single phase material. This phenomenon has the potential to control the magnetic state of a material with an electric field, an enticing prospect for device engineering. We demonstrate 'giant' magnetoelectric cross-field control in a single phase rare earth titanate film. In bulk form, EuTiO3 is antiferromagnetic. However, both anti and ferromagnetic interactions coexist between different nearest neighbor europium ions. In thin epitaxial films, strain can be used to alter the relative strength of the magnetic exchange constants. Here, we not only show that moderate biaxial compression precipitates local magnetic competition, but also demonstrate that the application of an electric field at this strain state, switches the magnetic ground state. Using first principles density functional theory, we resolve the underlying microscopic mechanism resulting in the EuTiO3 G-type magnetic structure and illustrate how it is responsible for the 'giant' cross-field magnetoelectric effect.