The self-diffusion coefficients of O ions in La1-xSrxFeO3 were determined by measuring the rate of gas-solid exchange of 18O at temperatures of between 800 and 1050C. It was found that the O diffusivity depended upon the Sr content. The temperature variations of the volume diffusivities were described by the Arrhenius relationships:

LaFeO3:     D (cm2/s) = 8.40 x 10-7 exp[-134.0(kJ/mol)/RT]

La0.6Sr0.4FeO3:     D (cm2/s) = 7.19 x 10-7 exp[-120.3(kJ/mol)/RT]

La0.4Sr0.6FeO3:     D (cm2/s) = 1.96 x 10-6 exp[-95.7(kJ/mol)/RT]

SrFeO3:     D (cm2/s) = 2.10 x 10-6 exp[-87.9(kJ/mol)/RT]

Thus, the behavior of the volume diffusion as a function of composition was markedly affected by the diffusivity of the end-members. The volume diffusion at x = 0.6 behaved like that at x = 1, and the volume diffusion at x = 0.4 behaved like that at x = 0.

M.C.Kim, S.J.Park, H.Haneda, J.Tanaka, T.Mitsuhasi, S.Shirasaki: Journal of Materials Science Letters, 1990, 9[1], 102-4