The diffusivity, at between 200 and 500C, was determined by using a serial sectioning technique (figure 14).

V.N.Alfeev, P.P.Gorbik, V.V.Dyakin, F.A.Zaitov, V.M.Ogenko, G.M.Shalyapina: Solid State Communications, 1991, 77[1], 49-51