Synthesis, structure, superconducting and magnetic properties of (Ru1-x5+ Mox6+)(Sr,Gd)2(Gd0.7Ce0.34+ )2Cu2O10-d (x = 0.0, 0.25, 0.50, 0.75, 1.0)

We report results of the structural, electrical and magnetic studies in synthesized (Ru1-xMox)Sr2(Gd0.7Ce0.3)2Cu2-O10-* d (x = 0.0, 0.25, 0.50, 0.75, 1.0) system. The RuSr2(Gd0.7Ce0.3)2Cu2O10-*d phase (x = 0) may be both non-superconducting and superconducting with the transition temperature Tc(onset) = 32 or 46 K depending on annealing conditions. Annealing under high oxygen pressure shifts Tc to higher temperatures that is caused by change of cation composition. In the (Ru1-xMox)Sr2(Gd0.7Ce0.3)2Cu2O10-*D system, lattice parameters of the different phases corresponding to the different composition decrease with increasing of Mo ions content. This is explained by tetrahedral coordination of Mo ions. The substitution of Mo for Ru suppresses the superconductivity: the phases with x = 0.25 and 0.50 are superconductors with Tc(onset) = 25 and 22 K, respectively, the phases with x = 0.75 and 1.0 show a semiconductive behavior. A magnetic ordering is observed near by ~95 K for all phases.