Combined PAC and electron-channeling studies of He-defect interaction in CU between 300 and 900 K

Abstract

The interaction of He atoms with defects in ‘“In-implanted Cu single crystals was investigated by simultaneous perturbed γγ-angular correlation (PAC) and conversion-electron channeling measurements during annealing in the temperature range 300 to 900 K. Below 600 K different He-defect complexes were formed with large fractions of In probe atoms, which are increasing with annealing temperature. No significant displacements of substitutional In atoms occur, however, as concluded from the unchanged electron channeling effects. Above 700 K the channeling effects vanish completely, but a unique quadrupole interaction is observed in the PAC spectra for a large part (25-40%) of the probe atoms. It is proposed that He bubble growth is responsible for the vanishing of the channeling effects and that In atoms are attached to these bubbles on a unique, well-defined site.