Induced magnetic moment on Rh in the (FexRh1−x)100−yBy amorphous system

Abstract The magnetic properties of the (FeRh) 100− y B y ( y =20,25) amorphous system have been investigated by AC susceptibility, DC magnetization and 57 Fe Mossbauer spectroscopy. The experimental data give strong evidence for the presence of a sizable moment on Rh. Our data suggest that the moment on Rh evolves discontinuously, existing only when it has at least four Fe nearest neighbours. While the condition for the appearance of the moment on Rh is identical in both the a-(FeRh) 75 B 25 and a-(FeRh) 80 B 20 systems, the magnitude of the induced moment decreases despite an enhancement in the average ferromagnetic exchange in the Boron-rich system. We show that the induced Rh moment is correlated to the Fe–Rh exchange and there are indications of induced moment on Rh even in the paramagnetic state.