Exchange Biasing of the Ferromagnetic Semiconductor Ga1-xMnxAs

TL;DR

This paper reports the experimental demonstration of exchange biasing in a ferromagnetic semiconductor (Ga1-xMnxAs) coupled with an antiferromagnet (MnO), showing a shift in hysteresis loops and enhanced coercivity.

Contribution

It introduces the first observation of exchange bias in Ga1-xMnxAs coupled with MnO, with comparable blocking and Curie temperatures.

Findings

Exchange bias observed as a shift in hysteresis loop.

Enhanced coercive field in the bilayer.

Blocking temperature close to Curie temperature.

Abstract

We demonstrate the exchange coupling of a ferromagnetic semiconductor (Ga1-xMnxAs) with an overgrown antiferromagnet (MnO). Unlike most conventional exchange biased systems, the blocking temperature of the antiferromagnet (T_B = 48 +- 2 K) and the Curie temperature of the ferromagnet (T_C = 55.1 +- 0.2 K) are comparable. The resulting exchange bias manifests itself as a clear shift in the magnetization hysteresis loop when the bilayer is cooled in the presence of an applied magnetic field and an enhancement of the coercive field.