Coherent magnetization precession in ferromagnetic (Ga,Mn)As induced by picosecond acoustic pulses

TL;DR

This paper demonstrates that picosecond acoustic pulses can induce and control coherent magnetization precession in a ferromagnetic (Ga,Mn)As layer by modulating its magneto-crystalline anisotropy.

Contribution

It introduces a method to manipulate magnetization dynamics using ultrafast acoustic pulses in ferromagnetic semiconductors.

Findings

Picosecond strain pulses tilt the magnetization vector.

Magnetization precession is induced and can be modeled by anisotropy changes.

A single anisotropy constant change explains the observed dynamics.

Abstract

We show that the magnetization of a thin ferromagnetic (Ga,Mn)As layer can be modulated by picosecond acoustic pulses. In this approach a picosecond strain pulse injected into the structure induces a tilt of the magnetization vector M, followed by the precession of M around its equilibrium orientation. This effect can be understood in terms of changes in magneto-crystalline anisotropy induced by the pulse. A model where only one anisotropy constant is affected by the strain pulse provides a good description of the observed time-dependent response.