Effect of local environment on formation of local moments in BCC Fe-V alloys: Mossbauer study

Abstract

The Mossbauer spectra of BCC Fe-V alloys in the concentration range 40-80 at.% V have been obtained for both the ordered and disordered states. No broadening of the absorption line has been detected in an 80 at.% V alloy even at liquid He temperature indicating that the alloy is nonmagnetic. Broadening of absorption lines due to the magnetic hyperfine field has been observed for the alloys containing less than 70 at.% V. The spectra obtained at 5K were analysed to yield the hyperfine field distribution curves. It was found that the hyperfine field is notably reduced by atomic ordering. This change in hyperfine field is explained as the result of the change in Fe atomic moment which increases with increasing the number of Fe nearest neighbours. Profiles of the hyperfine field distribution curves are explained on the same basis. The dependence of the Fe atomic moment on the near-neighbour Fe composition is compared with the result of CPA calculations. Correlation between the lattice constant and the magnetic moment is discussed.