Large Nonlinear Kerr Angle in non-Centrosymmetric Fe/AlGaAs (001)Heterostructure

TL;DR

This paper reports a significant nonlinear magneto-optical Kerr effect in a non-centrosymmetric Fe/AlGaAs heterostructure, driven by interference of optical waves from magnetic and crystallographic origins, with potential for high-sensitivity magnetization detection.

Contribution

It demonstrates a large nonlinear Kerr rotation in Fe/AlGaAs heterostructures due to interference effects, revealing a new mechanism for enhanced magneto-optical responses.

Findings

Nonlinear Kerr rotation of 1.6 degrees observed

Effect is two orders of magnitude stronger than linear Kerr effect

High magnetic contrast along all in-plane directions

Abstract

A large nonlinear magneto-optical effect is observed in a non-centrosymmetric Fe/AlGaAs (001) heterostructure. This effect is a direct consequence of interference between second-harmonic optical waves of magnetic and crystallographic origin, generated at ferromagnetic Fe interface and bulk AlGaAs, respectively. The longitudinal nonlinear Kerr rotation is measured to be 1.6 degrees along the [1-10] hard axis, about two orders of magnitude stronger than the linear equivalent. The rotational second-harmonic signal shows large magnetic contrast along all the in-plane directions, demonstrating a high sensitivity to the magnetization of an anisotropic interface in the longitudinal geometry.