Crystallographic, magnetic and electric studies of a new pyrochlore-like structure (Bi1.56Co0.44)(Sb1.48Co0.52)O7 compound

Abstract: A new pyrochlore-type structure (Bi1.56Co0.44)(Sb1.48Co0.52)O7 compound has been synthesized using ceramic method in air. Rietveld refinements using X-ray powder diffraction data confirmed an overall A2B2O7 cubic pyrochlore structure with a =10.44896 (2)Å and Fd-3m symmetry. The reliability factors are R wp =3.09%; R p =2%; R exp =1.39% and R Bragg =4.38%. The magnetic susceptibility measurements achieved between 4 and 800K indicate a paramagnetic behaviour with an oxidation state “+2” of the cobalt ion. The electric resistivity measured using the complex impedance spectroscopy method evidenced an increase of the electric conductivity with the temperature, which reached 1.88×10−3 (ohmcm)−1 at 775K. [Copyright &y& Elsevier]