Magnetic Properties of Short Period InGaMnAs/InGaAs Superlattices

TL;DR

This study investigates the magnetic phase transition in short period InGaMnAs/InGaAs superlattices, revealing that certain layer thicknesses exhibit a paramagnetic-to-ferromagnetic transition independent of band offsets.

Contribution

It demonstrates the occurrence of a paramagnetic-to-ferromagnetic phase transition in short period superlattices and shows this transition's independence from band offsets for specific layer thicknesses.

Findings

Paramagnetic-to-ferromagnetic transition observed.

Transition temperature independent of band offsets for certain layers.

Magnetic layers act as deep potential wells or barriers.

Abstract

We have observed a paramagnetic-to-ferromagnetic phase transition in short period InGaMnAs/InGaAs superlattices. The thicknesses of magnetic InGaMnAs layers in the structures studied was chosen to be 4 or 8 molecular layers (12 \AA or 24 \AA). The nonmagnetic InGaAs spacer layers are 12 \AA thick. The In content of InGaMnAs and InGaAs layers was chosen in such a way that magnetic layers were: deep potential wells, high potential barriers or shallow potential wells. For superlattices with 8 monolayer thick InGaMnAs magnetic layers and 4 monolayer thick InGaAs nonmagnetic spacers the temperatures of paramagnetic-to-ferromagnetic phase transition do not depend on the band offsets between InGaMnAs and InGaAs adjusted by the In content.