The blocking effect of surface dislocations on oxygen tracer diffusion in SrTiO.

The existence of a polishing-induced damaged zone at the surface of standard, nominally undoped, single-crystal SrTiO3 is exploited in diffusion studies in order to investigate the interaction between oxygen vacancies and dislocations. Tracer diffusion profiles for such crystals are proposed to exhibit three features: a short feature arising from a surface space-charge layer; an intermediate, longer feature arising from the high density of dislocations in the damaged zone; and finally, a much longer feature corresponding to diffusion in the homogeneous bulk crystal. Quantitative information is provided by finite-element-method calculations.

Complex behaviour of vacancy point-defects in SrRuO3 thin films.

The behaviour of point defects in thin, epitaxial films of the oxide electrode SrRuO3 was probed by means of diffusion measurements. Thin-film SrRuO3 was deposited by means of pulsed laser deposition (PLD) on (100) oriented, undoped single crystal SrTiO3 substrates. (16)O/(18)O exchange anneals were employed to probe the behavior of oxygen vacancies.

Do dislocations act as atomic autobahns for oxygen in the perovskite oxide SrTiO3?

The transport properties of edge dislocations comprising a symmetrical 6° [001] tilt grain boundary in weakly acceptor-doped SrTiO3 were investigated by means of various experimental and computational techniques. Oxygen transport along the dislocation array was probed by means of (18)O/(16)O exchange experiments under (standard) oxidising conditions (pO2 = 5 × 10(-1) bar) and also under reducing conditions (pO2 = 7 × 10(-22) bar) at T = 973 K. In both cases, isotope profiles obtained by Secondary Ion Mass Spectrometry (SIMS) indicated no evidence of fast diffusion along the dislocation array.

Complex diffusion behavior of oxygen in nanocrystalline BaTiO3 ceramics.

(18)O/(16)O exchange annealing and subsequent Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis is used to investigate oxygen transport in dense, nanocrystalline (average grain size d ≈ 300 nm) ceramics of nominally un-doped BaTiO3. Isotope penetration profiles are obtained as a function of temperature, 973 < T/K < 1173, at an oxygen activity aO2 = 0.20 and as a function of oxygen activity, 0.