Sepideh Pourasad, Hamideh Shakeripour*, SeyedSajad Hosseini, Hadi Salamati

https://doi.org/10.1016/j.physc.2018.02.029

The effect of Co^2+,3+and Ca²⁺ substitution in Y³⁺ site in YBa₂Cu₃O_7-δ superconductor has been studied. The series of high temperature superconducting samples of Y_1-y-xCo_yCa_xBa₂Cu₃O_7-δ with 0≤x≤0.015 and y=0.020 were prepared by solid-state reaction method. The samples were characterized for phase purity and lattice parameter variations by X-ray diffraction. The AC susceptibility curves, c'(T), show that in reserving cobalt fixed sample with the optimum T_c, by substitution of divalent Ca²⁺ at the trivalent Y³⁺ site no sensitive increasing happen in the superconducting transition temperature.