A TEM study of the annealing behaviour of nickel implanted with dysprosium ions

Abstract

The annealing behaviour of Ni implanted with Dy ions has been studied by transmission electron microscopy and the results compared to other data for the same system. Implantation to doses of 10¹⁶ Dy⁺ ions/cm² is shown to result in a non-crystalline damage layer, a phenomenon not usually observed in metals following irradiation and reported here in detail for the first time. Annealing of the non-crystalline layer is shown to proceed in distinct stages, apparently related to the Dy mobility. Heating to 300°C produces a microcrystalline Ni arrange ment and further heating to ∼ 550°C results in recrystallization to a highly defected single crystal without significantly changing the Dy implant profile. At higher temperatures the annealing of these defects is accompanied by migration of the Dy via a Ni-rich compound to the surface where it forms an epitaxial oxide layer.