FEATURES OF BROAD MAGNETIC TRANSITION IN FERH THIN-FILM

The first-order antiferromagnetic (AFM)-ferromagnetic (FM) transition in a Fe47.8Rh52.2 thin film has been studied as a function 0 temperature, applied magnetic field and internal stress. Although the AFM to FM transition shows a steeper change at a certain critical temperature (T(c) = 320 K), the FM to AFM transition is not complete below 10 K. The field dependence of T(c) (dT(c)/dH) for the AFM to FM transition agrees with bulk reference data. It is found that peeling from the substrate causes (1) a T(c) increase (about 50-degrees), (2) an acceleration in the transformation from the FM to the AFM phase, (3) steepening of the transition, and (4) a decrease in transition width. Bulk pressure coefficient data (dT(c)/dP) is used to show that the increase in T(c) results from the release of a measured tensile stress of 7.5 kbar. Macroscopic and locally distributed stress are both strongly related to the instability of the transformation from the FM to the AFM phase, and the steep and wide transition in FeRh thin film.