The angular dependence of magnetization dynamics induced by a GHz range strain pulse

TL;DR

This paper investigates how the coupling between phonons and magnons in magnetization dynamics varies with angle, using time-resolved measurements and theoretical modeling to reveal angular dependencies in spin-wave resonances and magnetic echoes.

Contribution

It provides new insights into the angular dependence of phonon-magnon coupling in magnetization dynamics through experimental and theoretical analysis.

Findings

Spin-wave resonance frequency and amplitude depend on the magnetic field angle.

Magnetic echo signal amplitude varies with the out-of-plane angle.

Angles of external magnetic field and magnetic moment are crucial for phonon-magnon coupling.

Abstract

The dynamics of magnetization is important in spintronics, where the coupling between phonon and magnon attracts much attention. In this work, we study the angular dependence of the coupling between longitudinal-wave phonon and magnon. We investigated the magnetization dynamics using the time-resolved magneto-optical Kerr effect, which allows measuring spin-wave resonances and the magnetic echo signal. The frequency, mode number, and amplitude of the spin-wave resonance change with the out-of-plane angle of the external magnetic field. The amplitude of the magnetic echo signal caused by the strain pulse also changes with the angle. We calculate these angular dependences based on the Landau-Lifshitz-Gilbert equation and find that the angles of the external field and magnetic moment are important factors for the phonon-magnon coupling when phonon propagates in the thickness direction under the out-of-plane magnetic field.