Quasi-elastic neutron scattering and back-scattering spectrometry were used to determine the elementary jump vectors of diffusing Co atoms in the B2 phase. Measurements were performed on single crystals which contained 54 or 64at%Co. For both compositions, a maximum quasi-elastic broadening was observed near to a reciprocal lattice point that corresponded to a B2 superlattice reflection. This furnished unambiguous evidence of Co diffusion via nearest-neighbor jumps. The presence of high defect concentrations was deduced from residence times on the antistructure sites. The correlation of Co diffusion was found to be surprisingly weak. A diffusion mechanism was suggested which took advantage of the high degree of disorder and, therefore could not be described in terms of defined cycles.

Determination of the Elementary Jump of Co in CoGa by Quasielastic Neutron Scattering. M.Kaisermayr, J.Combet, H.Ipser, H.Schicketanz, B.Sepiol, G.Vogl: Physical Review B, 2001, 63[5], 054303 (8pp)