Self-diffusion in the B2-ordered alloy NiGa

Quasielastic neutron scattering (QNS) has been used to investigate the self -diffusion of Ni in the intermetallic B2-compound NiGa. Our studies have sh own that the Ni-atoms diffuse via nearest-neighbour jumps in contrast to th e next-nearest-neighbour jump mechanism proposed an the basis of tracer dif fusion experiments. The residence time of the Ni-atoms on the antistructure sites has been found to be of the order of 1/10 of the residence time on t he Ni-sublattice. From this proportion the vacancy concentration has been d erived. (C) 2000 Elsevier Science B.V. ALI rights reserved.