The presence of an intermediate tetragonal distortion during the metamagnetic phase transition in B2-FeRh - A new pathway for the magnetost

Understanding structural changes in materials possessing a magneto-structural phase transition is crucial to perceive the energy landscape during this phase transition. On a macroscopic scale, using simultaneous measurements of the electronic, magnetic and structural subsystem, we found a decoupling of the magnetic and structural subsystem during the change from the antiferromagnetic to the ferromagnetic phase in FeRh. Besides the two-step transition, strain measurements indicate the presence of an intermediate tetragonal distortion of the sample. Thus, we intend to perform high-resolution XRD measurements along the temperature-induced phase transition to observe whether the Bragg peaks split (confirming the tetragonal distortion of the lattice) or not (changes in the microstructure caused by tetragonal distortions). These results will help identify the lattice transformation pathway during the first-order phase transition and identify the driving force of the phase transition.