The diffusion of rare-earth elements was studied in yttrium aluminum garnet. The source of the diffusant was a mixture of alumina and the rare-earth element oxide. The diffusion profiles were measured using Rutherford back-scattering spectrometry. The Arrhenius relationship was:

D(m2/s) = 2.70 x 100 exp[-603(kJ/mol)/RT]

D.J.Cherniak: Physics and Chemistry of Minerals, 1998, 26[2], 156-63