Neutron diffraction studies of Nd2(Co<i>x</i>Fe1−<i>x</i>)17 alloys: Preferential site occupation and magnetic structure

Abstract

Rietveld analyses of room-temperature neutron powder diffraction data for seven Nd2(CoxFe1−x)17 alloys (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) are reported. In the ternary systems we find that the c-type transition metal sites are preferentially occupied by Fe ions; concomitantly, the d and h sites have Co occupations larger than those predicted by stoichiometry, while the f sites deviate only slightly from random occupation. The magnetic moments obtained from the data refinements indicate a transition from a low to a high spin state on the d, f, and h sites as Fe is incorporated into the structure; a reverse trend is exhibited by the moments on the c site.