On the formation of ion-bombardment-induced disorder in zircon, corundum and diamond (studies on bombardment-induced disorder—II)

Abstract

The release of Kr-85 from zircon, corundum, and diamond, following its injection at 10 keV, can be effected both by dissolution of surface layers disordered by the ion bombardment or alternatively by thermal annealing of the disorder. Such release was used to investigate the progress of disordering as a function of ion-bombardment dose. Both techniques were found to give comparable results and with zircon a close agreement with disordering by alpha recoils, as studied by Holland and Gottfried, was also found. The results are interpreted in terms of a threshold dose and a subsequent, rapid transformation of the crystalline solid into a disordered (amorphous) state. The mean numbers of atoms transferred to the disordered phase per ion impact were determined and found to be 300 for zircon, 150 for corundum, and 110 for diamond. A tentative explanation for this sequence is suggested based on the ease with which the disorder anneals.