The diffusion of Sr in single crystal BaTiO3 was investigated in air at between 1000 and 1250C. The diffusion profiles were measured by SIMS depth profiling on a time-of-flight secondary ion mass spectrometer. The diffusion coefficients of Sr were given by:

D(cm2/s) = 3.6 x 102exp[-543(kJ/mol)/RT]

S.Koerfer, R.A.De Souza, H.I.Yoo, M.Martin: Solid State Sciences, 2008, 10[6], 725-34