Oxygen diffusion in polycrystalline PrBaCo2O5+δ was studied using isotope exchange-depth profiling. Diffusion profiles of 18O were produced from secondary ion mass spectrometry depth profiles. High values of diffusivity, D* = 1.57 x 10−10cm2/s and k* = 4.9 x 10−8cm/s, were obtained at temperature as low as 350C. It was also observed that, at above 500C, the diffusion length exceeded 10μm; even for very short exchange times. Thus the extrapolation of diffusivity values became uncertain since the physical limit of depth profiling was approached. The results were compared with the existing literature and the discrepancies between the various values were analysed in terms of analysis technique, isotope exchange procedure and micro-structural effects.

Study of Oxygen Tracer Diffusion in PrBaCo2O5.74 by SIMS. R.Frison, S.Portier, M.Martin, K.Conder: Nuclear Instruments and Methods in Physics Research B, 2012, 273, 142-5