STRUCTURAL, MAGNETIC AND SUPERCONDUCTING PROPERTIES OF THE Y1-XZRXBA2-2XCA2XCU3O7-DELTA COMPOUNDS

Samples with stoichiometric composition Y1-xZrxBa2-2xCa2xCu3O7-delta w ith x = 0.0, 0.1, 0.2, 0.3 were prepared by the solid state reaction m ethod. The effect of Zr and Ca, doped at the Y and respectively Pa sit es simultaneously in the Y:123 composition was studied. The phase and lattice parameters of the compounds were determined by X-ray powder di ffraction measurements. We also discuss the distribution of the Ca ion s between the Y and Ba sites when Y is partially replaced by Zr. Super conductivity was analyzed by both electrical resistivity and magnetic susceptibility measurements. The results suggest the assumption that t he substitutions could increase the number of isolated Cu2+ spin 1/2 d efects and/or to change the energy of the spin fluctuations.