Synthesis of Ru_1-xSb_xSr₂(Eu _0.7Ce_0.3)₂Cu₂O_10-δ and their magnetic and transport properties

Ru_1-xSb_xSr₂(Eu_0.7Ce _0.3)₂Cu₂O_10-δ systems were prepared by conventional solid state reaction method. The structural analysis was investigated using X-ray diffraction. Electrical resistivity, Hall effect and magnetic susceptibility measurements on Ru:1222 doped with Sb are presented, together with results in the temperature range 5-300 K. Transition temperature decreases from 43 K for x = 0.00 to 20 K for x = 0.06 Sb. This may be due to a distortion of RuO₆ octahedral, which is responsible of the increase in hole localization. The Hall effect anomalous decreases below T _magnetic which may be explained within a simple two-band model by a transition from localized to more itinerant behavior in the RuO₂ layer at T_magnetic. The behavior of magnetic susceptibility is caused by an antisymmetric exchange coupling of the Dzyaloshinsky-Morya type between neighboring Ru moments.