Oxygen tracer diffusion in undoped lanthanum manganites

The oxygen tracer diffusion was studied in cation stoichiometric (LaMnO3 +/ - delta) and A-site deficient (La0.9MnO3 +/- delta) lanthanum manganites by the isotope exchange depth profiling (IEDP) technique using SIMS depth pro filing. The measured oxygen tracer diffusion coefficients were in the range of 10(-12) to 10(-15) cm(2) s(-1) and these values were comparable with th e ones determined in Sr-doped lanthanum manganites. The activation energy o f oxygen tracer diffusion was 240+/-23 kJ/mol in LaMnO3 +/- delta and 294 /- 11 kJ/mol in La0.9MnO3 +/- delta. A-site deficiency of up to 10% does no t affect oxygen tracer diffusion in these lanthanum manganites. Evidence fo r fast diffusion paths assigned to grain boundary diffusion was observed in the A-site deficient material. (C) 1999 Elsevier Science B.V. All rights r eserved.