THE PRESSURE EFFECT ON AU DIFFUSION IN AMORPHOUS PD40NI40P20

The activation volume for diffusion of ion-implanted Au in the amorpho us metal Pd40Ni40P20 has been determined from the pressure dependence of the diffusivity. Samples, in the well-relaxed state at 563 K prior to implantation, were annealed at 563.0 K for 12 h at pressures from 0 to 0.75 GPa. Au concentration profiles before and after annealing wer e determined by Rutherford-backscattering spectrometry (RBS). A gaussi an concentration profile was adjusted to fit the RB spectrum of Au, an d from the change in the width of the gaussian for samples annealed at various pressures. the diffusion coefficients and an activation volum e ((11 +/- 4) x 10(-3) nm3, i. e. close to the atomic volume of Au) we re determined. The effects of surface contamination and surface crysta llization on these results are considered and found to be negligible.