Magnetic and electrical properties of Ba2CrMo1 − xWxO6 double perovskite

Effects of the partial substitution of W^5+,6+ for Mo^5+,6+ on the structural and physical properties of Ba₂CrMoO₆ have been investigated. Polycrystalline Ba₂CrMo_1 − xW_xO₆samples have been prepared by sol-gel method in a stream of 5% Ar/H₂ gas at various sintering temperatures. Rietveld analysis of X-ray diffraction patterns shows a partial disorder of Mo/W and Cr on the B sites of the double perovskite, which plays a dominant role in the structural and magnetic properties of these compounds. The symmetry is cubic (Fm3?m) for all samples, and no phase transition was detected for Ba₂CrMo_1 − xW_xO₆. The Curie temperature T_C has been analyzed by two methods: a linear extrapolation of M(T) to zero magnetization and the thermodynamic model. The experimental results indicate that T_C decrease from 335 K (x = 0) to 285 K (x = 0.5) with increasing W substitution independently of the method used to obtain T_C. A systematic decrease in saturation magnetization, M_s with increasing W substitution has been observed in this solid solution series. This decrease of magnetization arises from the disorder at the Cr and Mo/W sites. Electrical properties change as well strongly along the series.