New Gd4-6-10 and Gd5-7-12 Cuprate Superconductors.

This paper describes the Gd_x−2Ba_xCu_2x−2O_δ (x = 6, 7) cuprate system synthesis using the conventional solid-state reaction method. Rietveld analysis of X-ray patterns evidences that samples crystallize in Pmm2 (#25) space group at room temperature with lattice parameter a = 3.8807 Å, b = 3.8735 Å, c = 38.7094 Å for Gd₄Ba₆Cu₁₀O_δ and a = 3.8680 Å, b = 3.8763 Å, c = 46.5065 for Gd₅Ba₇Cu₁₂O_δ. Resistivity measurements evidence zero-resistance state, which is a typical behavior of superconducting materials at bulk critical temperature of 15.5 K for Gd₄Ba₆Cu₁₀O_δ and 22.1 K for Gd₅Ba₇Cu₁₂O_δ. [ABSTRACT FROM AUTHOR]