Ferromagnetism and interlayer exchange coupling in short period (Ga,Mn)As/GaAs superlattices

TL;DR

This study investigates the magnetic properties and interlayer exchange coupling in short-period (Ga,Mn)As/GaAs superlattices, revealing a ferromagnetic transition near 60K and oscillating Curie temperatures influenced by spacer thickness.

Contribution

It demonstrates the existence of interlayer exchange interactions mediated by polarized holes, leading to oscillations in Curie temperature with spacer thickness in (Ga,Mn)As/GaAs superlattices.

Findings

Paramagnetic-to-ferromagnetic transition near 60K

Oscillations in Curie temperature with spacer thickness

Interlayer exchange interaction mediated by polarized holes

Abstract

Magnetic properties of (Ga,Mn)As/GaAs superlattices are investigated. The structures contain magnetic (Ga,Mn)As layers, separated by thin layers of non-magnetic GaAs spacer. The short period Ga$_{0.93}$Mn$_{0.07}$As/GaAs superlattices exhibit a paramagnetic-to-ferromagnetic phase transition close to 60K, for thicknesses of (Ga,Mn)As down to 23 \AA. For Ga$_{0.96}$Mn$_{0.04}$As/GaAs superlattices of similar dimensions, the Curie temperature associated with the ferromagnetic transition is found to oscillate with the thickness of non magnetic spacer. The observed oscillations are related to an interlayer exchange interaction mediated by the polarized holes of the (Ga,Mn)As layers.