Low-temperature magnetization study of crystalline and glassy Fe-B alloys

The low-temperature dependence of the magentization is reported for crystalline and glassy ${\mathrm{Fe}}_{100-x}{\mathrm{B}}_x$ alloys. Although the temperature coefficients reduced to the Curie temperatures are four to five times larger for the glassy alloys than the crystalline ones, all of the alloys exhibit Bloch's $T^{\frac{3}{2}}$ dependence. The spin-wave stiffness constant deduced from the temperature coefficient reaches a broad minimum ($D\sim 65$ meV Å${\mathrm{A}}^2$) for $x=14-16\mathrm{}$. This observation seems to be consistent with the Invar-like behavior reported recently for the similar alloys.