Synthesis, crystal structure and magnetic property of Sm2−xCoxTi2−xNbxO7 (x=0, 0.2, 0.4)

Sm2−xCoxTi2−xNbxO7 (x=0, 0.2, 0.4) were synthesized by a wet chemical method. The compounds possess pyrochlore structure with cubic face-central cell. The lattice parameter (a) is 1.0234 nm for Sm2Ti2O7, 1.0231 nm for Sm1.8Co0.2Ti1.8Nb0.2O7 and 1.0225 nm for Sm1.6Co0.4Ti1.6Nb0.4O7. Sm2Ti2O7 may possess the Van Vleck paramagnetism. The variation of the magnetic susceptibility of Sm2−xCoxTi2−xNbxO7 (x=0.2, 0.4) with temperature is similar to that of a ferrimagnet in the paramagnetic region. The satisfactory fitting to the experimental plot of the inverse susceptibility of Sm2−xCoxTi2−xNbxO7 (x=0.2, 0.4) vs. temperature indicates that the compounds may be a canted ferrimagnet.