Positron annihilation spectroscopy, using a variable energy beam, was used to investigate the variation in the vacancy-type defect density of films with various N concentrations. Decreases in the Doppler-broadened line-shape parameter were observed as the N partial pressure, which was used during preparation of the samples, was increased from 0.01 to 0.1Pa. It was proposed that this indicated a decrease in the positron trapping at vacancy defects within this range. It was suggested that the positrons were trapped in Ti vacancies, with the variation in trapping being due to increasing N-atom migration into Ti sub-lattice vacancy sites as the N partial pressure was increased.

A.P.Knights, A.S.Saleh, P.C.Rice-Evans, S.J.Bull, F.Elstner, F.Richter, H.Kupfer: Journal of Physics - Condensed Matter, 1996, 8[14], 2479-86