Self-diffusion coefficients were measured simultaneously in single crystals of MgSiO3 perovskite under lower mantle conditions. No anisotropy in the diffusion could be resolved. The diffusion at 25GPa was described by:

D(m2/s) = 4.99 x 10-11exp[-305(kJ/mol)/RT]

J.Xu, D.Yamazaki, T.Katsura, X.Wu, P.Remmert, H.Yurimoto, S.Chakraborty: Journal of Geophysical Research B, 2011, 116[12], 12205