Study of oxygen tracer diffusion in PrBaCo2O5.74 by SIMS

In this work we studied oxygen diffusion in polycrystalline PrBaCo2O5+δ by isotope exchange-depth profiling (IEDP). Diffusion profiles of 18O are produced from Secondary Ion Mass Spectrometry (SIMS) depth profiles. We obtained high values of diffusivity; D∗ = 1.57 × 10−10 cm2/s and k∗ = 4.9 × 10−8 cm/s; at temperature as low as 350 °C. We also observed that at temperatures higher than 500 °C, the diffusion length exceeds 10 μm even for very short exchange times, thus the extrapolation of diffusivity values became uncertain since the physical limit of depth profiling is approached. Our results are compared with existing literature and the discrepancies among the different values are discussed in terms of analysis technique, isotope exchange procedure and micro-structural effects.