Photoabsorption Study of the Fe-Ni-Se Alloy System

Abstract

(Fe_xNi_1-x)₁₁Se₈ is a body-centred tetragonal system in wich Ni can be partially substituted by Fe at 580°C in this phase provided 0.04<x<0.23 as reported by Røst and Haugsten (1969) who have also comprehensively studied its crystal structure. Terzieff(1976) made magnetic susceptibility measurements on the system between 100 and 300°K and found that it shows a decreasing temperature dependence with with progressive increase in the Fe content and display an approximate Curie-Weiss behaviour for x<0.14 samples with the possibility of going over to an antiferromagnetic behaviour at temperatures lower than 100°K. We have, therefore, made an x-ray absorption study of two of the (Fe_xNi₁-x)₁. Seg compounds, x=0.06 and x=0.22, which lie on either side of the far removed from the value x=0.14 at which the magnetic behaviour of the system is found to change.