Superconductivity up to 95 K in mercury-substituted 1212 thallium cuprates (Tl,Hg)1,Sr2 + yNd1 – yCu2O7 +δ

Abstract

The solid solution Tl_1–xHg_xSr_2+yNd_1–yCu₂O_7–δ has been characterized; the homogeneity range extends up to x= 0.2 and y= 0.5. Electron diffraction and XRD studies confirm the statistical distribution of the cations in the different sites of the 1212-type structure. The best properties are observed for x= 0.1 and y= 0.5, with a T_c of 95 K and a diamagnetic volume fraction of 70%. The influence of mercury substitution for thallium in the phase is discussed.