Data were presented on the evolution of the pyrochlore structure in Sm2+xHf2−xO7−δ (x = 0.096) solid solutions prepared from mechanically activated oxide mixtures. It was shown that Sm2.096Hf1.904O6.952 underwent pyrochlore to disordered pyrochlore to pyrochlore (P-P1-P) phase transformations at 1200 to 1670C. The former transformation led to an increase in the 840C conductivity from 10−4 to 3 x 10−3S/cm in samples synthesized at 1600C, and the latter led to a decrease in the 840C conductivity to 6 x 10−4S/cm in samples synthesized at 1670C. A reduction in the conductivity of Sm2.096Hf1.904O6.952 was accompanied by disappearance of the assumed superstructure. The highest 840C conductivities were exhibited by Sm2.096Hf1.904O6.952, synthesized at 1670C: with 7.5 x 10−3S/cm.

Structure and Electrical Conductivity of Ln2+xHf2−xO7−x/2 (Ln = Sm-Tb; x = 0, 0.096). A.V.Shlyakhtina, M.V.Boguslavskii, S.Y.Stefanovich, I.V.Kolbanev, A.V.Knotko, O.K.Karyagina, S.A.Borisov, L.G.Shcherbakova: Inorganic Materials, 2006, 42[5], 519-27