Abstract:
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.
bismuth; thallium; calcium; strontium; barium; yttrium; copper; oxides; superconductors
