Kβ−to−Kαx-ray intensity ratio studies of the valence electronic structure of Fe and Ni inFexNi1−xalloys

Abstract

$K\ensuremath{\beta}\ensuremath{-}\mathrm{t}\mathrm{o}\ensuremath{-}K\ensuremath{\alpha}$ x-ray intensity ratios of Fe and Ni in pure metals and in ${\mathrm{Fe}}_{x}{\mathrm{Ni}}_{1\ensuremath{-}x}$ alloys $(x=0.20,$ 0.50, 0.58) exhibiting similar crystalline structure have been measured following excitation by 59.54 keV $\ensuremath{\gamma}$ rays from a 200 mCi ${}^{241}\mathrm{Am}$ point source to understand why the properties of the ${\mathrm{Fe}}_{x}{\mathrm{Ni}}_{1\ensuremath{-}x} (x=0.2)$ alloy are distinct from other alloy compositions. The valence electronic structure of Fe and Ni in the samples has been evaluated by comparing the measured $K\ensuremath{\beta}\ensuremath{-}\mathrm{t}\mathrm{o}\ensuremath{-}K\ensuremath{\alpha}$ intensity ratios with the results of multiconfiguration Dirac-Fock calculations. Significant changes in the $3d$ electron population (with respect to the pure metal) are observed for Fe and Ni for certain alloy compositions. These changes can be explained by assuming rearrangement of electrons between $3d$ and $(4s,4p)$ band states of the individual metal atoms. It has been found that the valence electronic structure of the ${\mathrm{Fe}}_{0.2}{\mathrm{Ni}}_{0.8}$ alloy is totally different from the other two alloys, which perhaps is connected to the special magnetic properties of this alloy.