Detection of the magneto-structural phase coexistence in MnAs epilayers at a very early stage

TL;DR

This study uses ferromagnetic resonance to detect early-stage coexistence of magnetic phases in MnAs epilayers, revealing stripe formation in MnAs/GaAs(100) at temperatures below the ferromagnetic transition.

Contribution

It demonstrates the detection of magneto-structural phase coexistence and stripe formation in MnAs epilayers at an early stage using FMR, highlighting substrate-dependent growth behavior.

Findings

Magnetic stripes appear in MnAs/GaAs(100) below the ferromagnetic transition.

Early-stage phase coexistence is detectable via FMR.

Stripe formation differs between (100) and (111) GaAs substrates.

Abstract

We report on the appearance of magnetic stripes in MnAs/GaAs(100) epilayers at temperatures well below the ferromagnetic transition of the system. The study has been performed by ferromagnetic resonance experiments (FMR) on MnAs epilayers grown on (100) and (111) GaAs substrates. The FMR spectra of the MnAs/GaAs(100) samples at 180 K reveal the appearance of zones of different magnetic behavior with respect to the low-temperature homogeneous ferromagnetic phase. The angular and the temperature dependence of the spectra serve us to detect the inter-growth of the non-magnetic phase into the ferromagnetic phase at a very early stage of the process. The experimental data show that the new phase nucleates in a self-arranged array of stripes in MnAs/GaAs(100) thin films while it grows randomly in the same films grown on GaAs(111).