Selective spin wave excitation in ferromagnetic (Ga,Mn)As layers by picosecond strain pulses

TL;DR

This paper demonstrates selective excitation of a specific spin wave mode in ferromagnetic (Ga,Mn)As layers using picosecond strain pulses, revealing a new mechanism for controlling spin dynamics via magnon-phonon interactions.

Contribution

It introduces a novel method for selective spin wave excitation based on spatial matching of magnon and phonon eigenfunctions in ferromagnetic semiconductors.

Findings

Single frequency magnetization precession observed under certain magnetic fields.

Selective excitation explained by magnon-phonon eigenfunction matching.

Provides insight into controlling spin waves via strain pulses.

Abstract

We demonstrate selective excitation of a spin wave mode in a ferromagnetic (Ga,Mn)As film by picosecond strain pulses. For a certain range of magnetic fields applied in the layer plane only a single frequency is detected for the magnetization precession. We explain this selectivity of spin mode excitation by the necessity of spatial matching of magnon and phonon eigenfunctions, which represents a selection rule analogous to momentum conservation for magnon-phonon interaction in bulk ferromagnetic materials.