Magnetization reversal and anomalous coercive field temperature dependence in MnAs epilayers grown on GaAs(100) and GaAs(111)B

TL;DR

This study investigates the magnetic properties and magnetization reversal mechanisms of MnAs epilayers grown on different GaAs substrates, revealing an anomalous temperature dependence of coercivity linked to phase nucleation.

Contribution

It provides new insights into the temperature-dependent coercivity behavior and domain reversal mechanisms in MnAs epilayers on different substrate orientations.

Findings

Reentrant coercivity behavior above 200 K observed in all samples.

Magnetization reversal occurs via domain movement in both substrate orientations.

Anomalous coercivity linked to nucleation of β-phase at high temperatures.

Abstract

The magnetic properties of MnAs epilayers have been investigated for two different substrate orientations: GaAs(100) and GaAs(111). We have analyzed the magnetization reversal under magnetic field at low temperatures, determining the anisotropy of the films. The results, based on the shape of the magnetization loops, suggest a domain movement mechanism for both types of samples. The temperature dependence of the coercivity of the films has been also examined, displaying a generic anomalous reentrant behavior at T$>$200 K. This feature is independent of the substrate orientation and films thickness and may be associated to the appearance of new pinning centers due to the nucleation of the $\beta$-phase at high temperatures.