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

This paper describes the Gd x −2 Ba x Cu 2 x −2 O 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 Pmm 2 (#25) space group at room temperature with lattice parameter a = 3.8807 Å, b = 3.8735 Å, c = 38.7094 Å for Gd 4 Ba 6 Cu 10 O δ and a = 3.8680 Å, b = 3.8763 Å, c = 46.5065 for Gd 5 Ba 7 Cu 12 O δ . Resistivity measurements evidence zero-resistance state, which is a typical behavior of superconducting materials at bulk critical temperature of 15.5 K for Gd 4 Ba 6 Cu 10 O δ and 22.1 K for Gd 5 Ba 7 Cu 12 O δ .