Coupled atomic motion and spin-glass transition in FeAl2

TL;DR

This study investigates the interplay between atomic vibrations and spin-glass transition in FeAl2, revealing that vibrational modes freeze out concurrently with magnetic spin freezing below 35 K, using Mossbauer spectroscopy and x-ray diffraction.

Contribution

It demonstrates a coupled atomic and spin-glass transition in FeAl2, highlighting the simultaneous freezing of vibrational modes and magnetic spins.

Findings

Vibrational mode freezes out at spin-glass transition temperature

Anomalous change in Debye-Waller factor below 35 K

Concurrent atomic and magnetic freezing observed

Abstract

We have used 57Fe Mossbauer spectroscopy and x-ray diffraction to study the magnetic and vibrational properties of FeAl2. FeAl2 is an ordered intermetallic with a large Fe local moment, and a complex crystal structure with site-occupation disorder on some sites. This material exhibits spin-glass freezing below 35 K. From the 57Fe recoilless fraction, we find that there is a vibrational mode which freezes out concurrently with the spin freezing. X-ray powder diffraction measurements confirm this result, indicating an anomalous change in the Debye-Waller factor at temperatures below the spin-freezing temperature.