Magnetic and transport properties Ru_1-χSbχSr₂(Sm_0.7 Ce_0.3)₂Cu₂O_10-δ compounds

We have investigated the effect of the partial substitution of Sb for Ru in Ru_1-χSbχSr₂(Sm_0.7 Ce_0.3)₂Cu₂O_10-δ, (Ru:1222) prepared by conventional solid state reaction method, using X-ray diffraction analysis, electrical resistivity and DC-magnetic susceptibility measurements. Sb doping reduces the conductivity of the system and the onset superconducting transition temperature decreases from 42 K for χ = 0 to 21 K for χ = 0.06. This maybe due to a distortion of RuO₆ octahedral, which is responsible of the increase in hole localization. The corresponding magnetic moment in the investigated samples is about 0.1 μB for Ru. Furthermore we discuss the influence of phase composition on superconducting and magnetic order.