Observation of predicted superconductivity in Gd 1.4Ce 0.6Sr 2Cu 2TiO x with x ≈ 10

Abstract

Gd 2− z Ce z Sr 2Cu 2TiO x with x ≈ 10 is shown to exhibit granular superconductivity (as detected both by ESR measurements demonstrating a mesoscopic Meissner effect and by the onset of vortex dissipation in an applied field H ) for z ≈ 0.6. T c for the material, whose doping has not been optimized, is ≈ 11 K with a 90%–10% transition width of ΔT c ≈ 3 K.