Polycrystalline samples with a nominal composition Ru 1-x Sb x Sr 2 GdCu 2 O 8-d were prepared by a solid state reaction technique. A mixture of RuO 2, Sb 2 O 3, Gd 2 O 3, SrCO 3 and CuO was used to obtain the samples. We performed X-ray diffraction analyses, DC susceptibility and transport measurements and the studies showed that the samples were almost pure Ru -1212 phase. We also observed that Sb doping reduce the conductivity of the system and the transition temperature decreases with increasing Sb content. This may be due to a distortion of RuO 6 octahedral which is responsible for the increase of holes localization.

Ru 1-x Sb x Sr 2( Eu 0.7 Ce 0.3)2 Cu 2 O 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 RuO 6 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 RuO 2 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.

Polycrystalline samples of Ru 1−x SbxSr 2 GdCuO 8 doped with Sb, in which magnetic order and superconductivity coexist with T magnetic Tc, were prepared by a solid state reaction technique. Lattice parameters, electrical resistivity, Hall and thermopower coefficients measurements on the same sintered ceramic samples are presented.Both Hall effect and thermopower show anomalous decreases below T magnetic which might be explained with a simple two-band model in the RuO 2 layer at T magnetic . It was also observed that the Sb doping reduce the conductivity of the system and the transition temperature decreases with increasing Sb content. This may be due to a distortion of RuO 6 octahedra which is responsible for the increase of hole localization.

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Magnetotransport data on MgB 2 thin films, fabricated on Al 2 O 3 substrates using electron–bean deposition and Mg diffusion method are reported for applied magnetic fields up to 9 T. The upper critical field anisotropy, lower critical field and irreversibility field versus temperature are determined. The Hall coefficient is slightly temperature-dependent and positive in the normal state. Using the extracted data, the electronic mean free path, coherence length ξ0, anisotropic coefficient γ and penetration depth λ are calculated.