Moessbauer study of atomic order in the Ni3Fe alloy

The atomic ordering of the Ni3Fe alloy was investigated using the Moessbauer effect technique. A method for determining the short range order parameter sigma from the Moessbauer spectrum in the first neighbouring shell approximation is proposed. The obtained temperature behaviour of sigma gives a qualitative and quantitative picture of the ordering process in the investigated system. The influence of the Ni atoms in the nearest and next nearest neighbouring shells (the latter as a correcting factor) on the hyperfine field at the 57Fe nucleus characterized by the values ΔH1=-10.5 kOe/Ni atom, ΔH2=-4.1 kOe/Ni atom was determined from the dependence of the hyperfine field parameters on the degree of order. The study is supplemented by electrical resistivity measurements which indicate the changes of the long range order. (author)