Nonlinear magnetization dynamics of antiferromagnetic spin resonance induced by intense terahertz magnetic field

TL;DR

This study investigates how intense terahertz magnetic fields induce nonlinear magnetization dynamics in HoFeO3, revealing a significant magnetization change and a quadratic decrease in resonance frequency, modeled by a modified Landau-Lifshitz-Gilbert equation.

Contribution

It demonstrates the nonlinear response of antiferromagnetic resonance to strong terahertz fields and introduces a phenomenological damping model to describe this behavior.

Findings

Terahertz magnetic field causes ~40% change in magnetization.

Resonance frequency decreases quadratically with magnetization.

Modified Landau-Lifshitz-Gilbert equation accurately models the dynamics.

Abstract

We report on the nonlinear magnetization dynamics of a HoFeO3 crystal induced by a strong terahertz magnetic field resonantly enhanced with a split ring resonator and measured with magneto-optical Kerr effect microscopy. The terahertz magnetic field induces a large change (~40%) in the spontaneous magnetization. The frequency of the antiferromagnetic resonance decreases in proportion to the square of the magnetization change. A modified Landau-Lifshitz-Gilbert equation with a phenomenological nonlinear damping term quantitatively reproduced the nonlinear dynamics.