Broadband electrical detection of spin excitations in (Ga,Mn)As using a photovoltage technique

TL;DR

This paper demonstrates broadband microwave detection of spin excitations in (Ga,Mn)As using a photovoltage technique, revealing detailed magnetic properties and relaxation mechanisms, and highlighting its potential for studying ferromagnetic semiconductors.

Contribution

It introduces a broadband photovoltage method for detecting spin excitations in (Ga,Mn)As, enabling detailed analysis of magnetic resonance and relaxation processes.

Findings

Detected ferromagnetic resonance from 2 GHz to 18.5 GHz

Determined spectroscopic g-factor and relaxation contributions

Showed temperature-dependent sensitivity to crystal anisotropy

Abstract

We report on microwave photovoltage and simultaneous magnetotransport measurements in a (Ga,Mn)As film oriented normal to the magnetic field. We detect the ferromagnetic resonance over a broad frequency range of 2 GHz to 18.5 GHz and determine the spectroscopic g-factor and separate the Gilbert from the inhomogeneous contribution to magnetization relaxation. Temperature dependent measurements below the saturation magnetization indicate that the photovoltage signal can serve as a sensitive tool to study the crystal anisotropy. We demonstrate that the combination of spin dynamics with charge transport is a promising tool to study microstructured ferromagnetic semiconductor samples.