Tracer diffusion of O was studied in cation stoichiometric, LaMnO3, and A-site deficient, La0.9MnO3, specimens by means of the isotope-exchange depth-profiling technique; using secondary ion mass spectrometry. The measured O tracer diffusion coefficients ranged from 10-12 to 10-15cm2/s. These values were comparable to those found for Sr-doped lanthanum manganites. The activation energy for O tracer diffusion was 240kJ/mol in LaMnO3, and 294kJ/mol in La0.9MnO3. An A-site deficiency of up to 10% did not affect O tracer diffusion in the lanthanum manganites. Evidence was found for rapid diffusion in the A-site deficient material. This was attributed to grain boundary diffusion.
Oxygen Tracer Diffusion in Undoped Lanthanum Manganites. A.V.Berenov, J.L.MacManus-Driscoll, J.A.Kilner: Solid State Ionics, 1999, 122[1-4], 41-9
Table 116
Oxide Ion Conductivities of LaMnO3
Temperature(K) | PO2 (bar) | (S/cm) |
973 | 0.2 | 4.78 |
973 | 10-5 | 4.78 |
973 | 10-6 | 4.78 |
973 | 10-7 | 4.23 |
973 | 10-9 | 4.02 |
973 | 10-11 | 3.92 |
923 | 0.2 | 5.17 |
923 | 10-5 | 5.17 |
923 | 10-6 | 5.17 |
923 | 10-7 | 4.51 |
923 | 10-9 | 4.31 |
923 | 10-11 | 4.02 |
873 | 0.2 | 5.69 |
873 | 10-5 | 5.69 |
873 | 10-6 | 5.14 |
873 | 10-7 | 4.95 |
873 | 10-9 | 4.77 |
873 | 10-11 | 4.62 |