Optomagnetic non-thermal modification of the ferromagnetic resonance

TL;DR

This paper demonstrates that linearly polarized light can non-thermally modify ferromagnetic resonance frequencies via the inverse Cotton-Mouton effect, supported by analytical theory, simulations, and experimental data.

Contribution

It provides a theoretical framework and analytical expressions for photoinduced FMR shifts due to ICME, highlighting a non-thermal control mechanism.

Findings

FMR frequency depends on light polarization angle and direction.

ICME-induced frequency shift can surpass thermal effects.

Analytical results align with simulations and experimental data.

Abstract

We investigate the photoinduced shift of the ferromagnetic resonance (FMR) frequency in magnets caused by the inverse Cotton-Mouton effect (ICME) under linearly polarized light. Using a Lagrangian description of magnetization dynamics, we derive the equations of motion, and obtain analytical expressions for the resonance frequency in both in-plane and out-of-plane equilibrium configurations. The theory shows that the FMR frequency depends on the polarization angle and propagation direction of light, with ICME producing a frequency shift that can dominate over thermal effects. The analytical results agree well with numerical simulations and with available experimental data for bismuth-substituted yttrium iron garnet, enabling estimation of the ICME contribution. These findings demonstrate that linearly polarized light can be used to control ferromagnetic resonance through magneto-optical effects.