Magnetic Properties of Single-Crystalline FeRh Alloy Thin Films

The structural and magnetic properties of single-crystalline Fe$_{100-{\rm X}}$Rh$_{{\rm X}}$ $(26 \leqq {\rm X} \leqq 63)$ grown on MgO (100) substrates were systematically studied as a function of composition, temperature and applied magnetic field. The first-order magnetic phase transition of Fe$_{100 - {\rm X}}$Rh$_{{\rm X}}$ was observed with the range of $51 \leqq {\rm X} \leqq 60$. The temperature dependent magnetization behavior for all the samples under investigation is presented. The transition temperature for the change from anti-ferromagnetic (AFM) to a ferromagnetic (FM) state vary between 70 to 150 $^{\circ}$C. The change in entropy, $\Delta$S, estimated by the change in transition temperature with applied magnetic field during cooling process, decreases with increasing X and at $X \cong 62$, it become zero. The observed hysteresis loop performed P-MOKE shows shaper transition as compared to VSM, indicates that surface magnetization distribution is different from the overall film.