The self-diffusion of Ca in single crystals of CaWO4 doped with Nd and Na was measured at 0.53Tm to 0.9Tm. From 0.75Tm to 0.9 Tm:

D(cm2/s) = 4.0 x 10-3 exp[-55800/RT]

and from 0.53 to 0.75Tm,

D(cm2/s) = 1.9 x 10-8 exp[-22900/RT]

Y.P.Gupta, L.J.Weirick: Journal of Physics and Chemistry of Solids, 1967, 28[12], 2545-52