Superconductivity in BiCaYSrCuO (2122) and TlCaYBaCuO (1122) systems: Effect of substitution of Ca by Y

Effect of substitution of Ca by Y on the properties of TlCaBa2Cu2O7 (1122) and Bi2CaSr2Cu2O8+δ (2122) has been studied. Lattice parameters vary progressively with increase in Y concentration in both the systems. In TlCa1−xYxBa2Cu2O7+δ , compositions with x ≤ 0.5 are superconducting. In Bi2Ca1−xYxSr2Cu2O8+δ , compositions with x <0.5 are superconducting; oxides of both these systems become semiconducting for higher values of x. In Bi-(Ca, Y, Sr)3 Cu2O8+δ , Tc decreases with the increasing Y/Ca ratio becoming zero at a finite value of the ratio.