Mössbauer study of amorphous Fe78B12Si10

Abstract

Amorphous ${\mathrm{Fe}}_{78}$ ${\mathrm{B}}_{12}$ ${\mathrm{Si}}_{10}$ in ribbon form has been investigated over a large temperature range from 4.2 to 750 K using the Mössbauer technique. The average isomer shift, although less than that for crystalline iron at 4.2 K, has a similar temperature dependence. The average quadrupole shift is zero below the Curie temperature $T_F$. The average hyperfine field is proportional to ${\left(\frac{T}{T_F}\right)}^{\frac{3}{2}}$ for $0.03<~\frac{T}{T_F}<~0.5$, but varies more slowly for $\frac{T}{T_F}<~0.03$. The conduction electrons appear to play an important role in reducing the importance of the amorphous nature of the alloy. The magnetization of a clamped sample, nearly randomly oriented at or below room temperature, lies mainly in the plane of the ribbon between 500 and 700 K. On returning to room temperature after annealing at 706 K, the magnetization has a large out-of-plane component.