Magnetic behaviour of the $Bi_{2-x}Sr_xIr_2O_7$ pyrochlore

Polycrystalline compounds of the $Bi_{2-x}Sr_xIr_2O_7$ solid solution have been synthesized. These compounds were obtained by the solid state reaction method in the $0 < x < 0.9$ range with the $\alpha$-pyrochlore crystal structure. This material was characterized with Crystalline Rietveld refinement and cyclic voltammetry. These analyzes permitted the understanding of the unit-cell modifications and valence states of Iridium as a function of the strontium content. Electrical characterization of samples in the $10$-$300K$ range shows a metallic character that remains for the whole solid solution. Magnetically this system behaves as a Curie-Weiss paramagnetic in the $2$-$300K$ range. The measured magnetic moment values suggest the presence of $Ir^{5+}$ in some compounds of the solid solution.