Influence of annealing parameters on the ferromagnetic properties of optimally passivated (Ga,Mn)As epilayers

TL;DR

This study examines how annealing temperature and time affect the magnetic transition temperature of (Ga,Mn)As thin films, revealing optimal conditions for high Tc regardless of film thickness.

Contribution

It provides new insights into optimizing annealing parameters to enhance ferromagnetic properties of (Ga,Mn)As epilayers.

Findings

Tc peaks at specific annealing times depending on film thickness

Optimal annealing yields Tc of ~150 K or higher

Passivation and growth conditions significantly influence magnetic properties

Abstract

The influence of annealing parameters - temperature and time - on the magnetic properties of As-capped (Ga,Mn)As epitaxial thin films have been investigated. The dependence of the transition temperature (Tc) on annealing time marks out two regions. The Tc peak behavior, characteristic of the first region, is more pronounced for thick samples, while for the second (`saturated') region the effect of the annealing time is more pronounced for thin samples. A right choice of the passivation medium, growth conditions along with optimal annealing parameters routinely yield Tc-values of ~ 150 K and above, regardless of the thickness of the epilayers.