Nuclear spin relaxation measurements were made of single crystals at temperatures of between 150 and 1500K, under an O partial pressure of 1atm. The nuclear magnetic resonance spectrum consisted of a doublet which resulted from 2 different orientations of the electric field gradient tensor at 2 different Ti sites in the unit cell of the rutile lattice. The electric field gradient tensor was due to the 6 surrounding O2- ions, which formed a stretched octahedron. From the temporal evolution of the nuclear spin relaxation rate after a step-wise change in the O partial pressure, 2 different types of motion of the intrinsic defects were deduced. It was found that the motion of interstitial Ti ions was described by the expression:

D (cm2/s) = 2.6 x 10-3exp[-0.42(eV)/kT]

while the motion of doubly-charged O vacancies was described by the expression:

D (cm2/s) = 9 x 10-6exp[-0.32(eV)/kT]

The use of site-selective nuclear spin relaxation methods revealed that some 1% of Ti diffusion occurred via jumps between the non-equivalent Ti lattice sites via a monovacancy process.

H.Kolem, O.Kanert: Zeitschrift für Metallkunde, 1989, 80[4], 227-34