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.
@article{arxiv.cond-mat/0308471,
title = {Coupled atomic motion and spin-glass transition in FeAl2},
author = {Yang Li and F. G. Vagizov and V. Goruganti and Joseph H. Ross, and Zuxiong Xu and Guohui Cao and Cheng Dong and Zhaosheng Feng},
journal= {arXiv preprint arXiv:cond-mat/0308471},
year = {2012}
}