Investigation on Critical Regime of Cu0.5Tl0.5Ba2(Ca2−x Be x )(Cu2Ti)O10−δ Superconductor via Excess Conductivity Analysis

Abstract

Superconducting Cu0.5Tl0.5Ba2(Ca2−x Be x ) (Cu2 Ti)O10−δ (x = 0, 0.5, and 1.0) samples were synthesized using a two-step solid-state reaction method. Superconducting properties were suppressed after Be substitution at Ca sites in these samples. Variation of oxygen phonon modes after Be doping was according to the masses of Ti (47.90 amu) and Cu (63.54 amu)atoms in conducting planes. Decrease in microscopic superconducting parameters deduced from excess conductivity analysis was attributed to an-harmonic oscillations, which have reduced Cooper pairs density from a desired level for optimum superconductivity.