Structural and microstructural transformations in Bi_2Sr_2Ca_(1-x)Y_xCu_2O_(8+y) system

Conclusions With the substitution of Y for Ca in BSCYCO system, both the hole concentration and structure parameters change. The superconductor-nonsuperconductor transition at xc = 0.4 is more sensitive to the structure transformation than the variation in the hole concentration. Microanalysis reveals an inhomogeneous substitution of Y for Ca. So a much sharper drop of T, is expected at transition point by ideal monophase samples of BSCYCO. A ratio of lattice constants c / o. 5 (a + b) is found to be a very good parameter of describing the SC-AF transition of ISCYCO, reflecting the degree of the localization of Cu-3d electrons on the CuOz plane.