Lattice instability in antiferromagnetic B2 FeRh

With this experiment, we want to investigate the theoretically predicted lattice instability in AFM FeRh in the B2 structure. In preliminary Fe K-edge EXAFS measurements, we observed the occurrence of a lattice distortion that can be modelled by assuming a B2-lattice with slight lattice distortions predicted by Wolloch et al. With the experiment, we want to investigate the local surrounding of the Fe and Rh atoms by EXAFS. Complementary, we plan to investigate the structural lattice instability by X-ray diffraction to further corroborate our spectroscopy results. As a last step, we aim at performing temperature-dependent measurements focussing on the lattice dynamics to investigate changes on the local surrounding around the Fe and Rh atoms (EXAFS) and the long-range order (XRD). Here, we specially want to investigate the effects and possible different structural response of the dynamically stabilised lattice instability on the short range, as well as on the long-range order.