Effects of yttrium and zinc substitutions in Bi-2212

In this work, resistivity measurements of Bi2Sr2Ca1-xYxCu2-yZnyO8+d were analyzed. The yttrium substitution on calcium site modifies the charge concentration and the zinc substitution on cupper site leads to a depression of the superconducting transition temperature TC. Beyond the superconducting transition, the resistivity curves show the compounds evolve from a metallic state to a semi-conducting state upon the yttrium and zinc substitutions. The semi-conductive behavior is explained by a random distribution of the substituted element. The evolution of the linear resistivity upon doping confirms the presence of heterogeneities. Moreover, the results suggest that zinc lead to a more effective states localization and stripes pinning