The serial sectioning technique was used to investigate the simultaneous diffusion of 85Sr and 57Co into single crystals with a divalent impurity concentration of about 5 x 10-7/cm3. The data for 600 to 750C could be described by:

D (cm2/s) = 6.4 x 10-6 exp[-0.96(eV)/kT]

in the near-surface region, and by:

D (cm2/s) = 2.8 x 10-3 exp[-1.06(eV)/kT]

in the bulk

A.R.Allnatt, P.Pantelis: Transactions of the Faraday Society, 1968, 64[8], 2100-5