Partial correlations in Ni Nb amorphous alloys

Short range order in amorphous Ni 44Nb 56 was investigated using time-of-flight neutron diffraction. The total structure factors were measured for three isotope substituted Ni 44Nb 56 samples with 58Ni, 60Ni, and 0Ni (a mixture of 62Ni and 60Ni isotopes with zero average coherent scattering amplitude). The partial structure factors, the atomic and the density-concentration correlation functions were determined. The characteristic parameters of the short range order are given, i.e., the neighbouring atomic pair distances, their distribution width and the coordination numbers. The results are compared with those given in the literature for amorphous Ni 62Nb 38, and the concentration dependence is analyzed in the amorphous Ni Nb system. It is established that chemical short range order is stronger in Ni-rich samples.