Spin-phonon interaction in yttrium iron garnet

Spin-phonon interaction is an important channel for spin and energy relaxation in magnetic insulators. Understanding this interaction is critical for developing magnetic insulator-based spintronic devices. Quantifying this interaction in yttrium iron garnet (YIG), one of the most extensively investigated magnetic insulators, remains challenging because of the large number of atoms in a unit cell. Here, we report temperature-dependent and polarization-resolved Raman measurements in a YIG bulk crystal. We first classify the phonon modes based on their symmetry. We then develop a modified mean-field theory and define a symmetry-adapted parameter to quantify spin-phonon interaction in a phonon-mode specific way in YIG. Based on this improved mean-field theory, we discover a positive correlation between the spin-phonon interaction strength and the phonon frequency.

Automated summary

This study investigates the spin-phonon interaction mechanism in a YIG crystal through temperature-dependent and polarization-resolved Raman measurements. The researchers classified the phonon modes in the magnetite and quantified the spin-phonon interaction using a modified mean-field theory. The results show a positive correlation between the spin-phonon interaction strength and the phonon frequency in YIG.