Origin of nonlinear magnetoelectric response in rare-earth orthoferrite perovskite oxides

TL;DR

This paper presents a theoretical analysis of the nonlinear magnetoelectric response in GdFeO$_3$, revealing that the nonlinearity stems from the non-linear change in Gd antiferromagnetic order under magnetic fields.

Contribution

The study introduces an analytical model combined with first-principles calculations to explain the origin of nonlinear magnetoelectric effects in rare-earth orthoferrite perovskites.

Findings

Reproduces experimental polarization changes under magnetic fields.

Identifies non-linear Gd antiferromagnetic order as the response origin.

Model applicable to other inversion-breaking antiferromagnetic materials.

Abstract

We report a theoretical study of the non-linear magnetoelectric response of GdFeO$_3$ through an analytical approach combined with a Heisenberg model which is fitted against first-principles calculations. Our theory reproduces the non-linear change of polarization under applied magnetic field reported experimentally such that it allows to analyze the origin of the large responses in the different directions. We show that the non-linear character of the response in these materials originates from the fact that the antiferromagnetic order of Gd atoms changes non-linearly with respect to the applied magnetic field. Our model can be generalized to other materials in which the antiferromagnetic ordering breaks inversion symmetry.