Fe57Mössbauer isomer shift in various amorphous Fe-base alloys

Abstract

Amorphous alloys of the type $A_{1-x}{\mathrm{Fe}}_x$ ($A=\mathrm{N}\mathrm{b},\mathrm{H}\mathrm{f},\mathrm{T}\mathrm{i},\mathrm{o}\mathrm{r}\mathrm{B}$) were prepared by means of coevaporation of the elements. The concentration dependence of the ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ Mössbauer isomer shift (IS) in these alloys was studied at room temperature. Values for the unstrained dilute limit $\delta {\left(\mathrm{IS}\right)}_{max}$ were obtained and analyzed in terms of the model of Miedema and van der Woude. Included in this analysis were data reported elsewhere for $A_{1-x}{\mathrm{Fe}}_x$ alloys with $A=\mathrm{T}\mathrm{h},\mathrm{Z}\mathrm{r},\mathrm{Y},\mathrm{M}\mathrm{g},\mathrm{S}\mathrm{n},\mathrm{G}\mathrm{e},\mathrm{a}\mathrm{n}\mathrm{d}\mathrm{S}\mathrm{b}$. It was found that the isomer shift can be represented by the general expression $\delta {\left(\mathrm{IS}\right)}_{max}=0.75\mathrm{}\Delta {\phi }^{*}-\frac{1.65\Delta n_{\mathrm{WS}}}{n_{\mathrm{WS}}^{\mathrm{Fe}}}$, where $\Delta {\phi }^{*}$ and $\Delta n_{\mathrm{WS}}$ represent, respectively, the difference in electronegativity and the difference in electron density at the atomic cell boundaries.