Investigation of magneto-structural phase transition in FeRh by reflectivity and transmittance measurements in visible and near-infrared spectral region

T Jungwirth,M Maryško,P Němec,F Trojánek,M Brajer,X Marti,T Janda,V Saidl,K Výborný,L Horák,H Reichlová,M Veis,I Fina

doi:10.1088/1367-2630/18/8/083017

Abstract

Magneto-structural phase transition in FeRh epitaxial layers was studied optically. It is shown that the transition between the low-temperature antiferromagnetic phase and the high-temperature ferromagnetic phase is accompanied by a rather large change of the optical response in the visible and near-infrared spectral ranges. This change is consistent with ab initio calculations of reflectivity and transmittance. Phase transition temperatures in a series of FeRh films with thicknesses ranging from 6 to 100 nm is measured thereby demonstrating the utility of the method to quickly characterise samples. Spatially resolved imaging of their magnetic properties with a micrometer resolution shows that the phase transition occurs at different temperatures in different parts of the sample.

Highlights

The near-equiatomic alloy of iron and rhodium undergoes a first-order magneto-structural transition from an antiferromagnetic (AF) to ferromagnetic (FM) phase around 380 K
We show that the AF to FM phase transition can be studied by the most straightforward optical experiment where the sample transmission and/or reflectivity is measured while the sample temperature is varied
Contrary to previous claims [17], we observe a clear change of optical properties of FeRh thin films upon crossing the AF to FM transition and find it to be most significantly pronounced in the near infrared spectral range

Summary

August 2016

It is shown that the transition between the low-temperature antiferromagnetic phase and the high-temperature ferromagnetic phase is accompanied by a rather large change of the optical response in the visible and near-infrared spectral ranges. This change is consistent with ab initio calculations of reflectivity and transmittance. Resolved imaging of their magnetic properties with a micrometer resolution shows that the phase transition occurs at different temperatures in different parts of the sample

Introduction

Samples and experimental setup

Reflectivity and transmittance: measurement and ab initio modelling

Spatially resolved measurements

Findings

Conclusions