Defect trapping of ion‐implanted deuterium in nickel

摘要

Trapping of ion‐implanted deuterium by lattice defects in nickel has been studied by ion‐beam‐analysis techniques in the temperature range between 30 and 380 K. The deuterium‐depth profiles were determined by measuring either the α particles or the protons from the 3He‐excited nuclear reaction D(3He,α)p, and the deuterium lattice location was obtained by means of ion channeling. Linear‐ramp annealing (1 K/min) following a 10‐keV D+ implantation in nickel produced two annealing stages at 275 and 320 K, respectively. The release‐vs‐temperature data were analyzed by solving the diffusion equation with appropriate trapping terms, yielding 0.24 and 0.43 eV for the trap‐binding enthalpies associated with the two stages, referred to as an untrapped solution site. The 0.24‐eV trap corresponds to deuterium close to the octahedral interstitial site where it is believed to be trapped at a vacancy, whereas it is suggested that the defect correlated with the 0.43‐eV trap is a multiple‐vacancy defect. The previously air‐exposed and electropolished nickel surface was essentially permeable; the surface‐recombination coefficient was determined to be K≳10-19 cm4/s at 350 K.