Some properties of YBamCu1+mOy(m = 2, 3, 4, 5) superconductors

Abstract

We synthesized the YBa m Cu 1+m O y superconductors; m = 2, 3, 4, 5 that were Y123 ( YBa 2 Cu 3 O 7-x), Y134 ( YBa 3 Cu 4 O 9-x), Y145 ( YBa 4 Cu 5 O 11-x), Y156 ( YBa 5 Cu 6 O 13-x), by solid state reaction with the Y 2 O 3, BaCO 3 and CuO as the beginning materials. The calcination temperature was 950°C and varied the sintering temperature to be 950°C and 980°C. The resistivity measurement by four-point-probe technique showed that the Tconset of Y123, Y134, Y145, Y156 were at 97, 93, 91, 85 K, respectively. The XRD and Rietveld full-profile analysis method were used and found that the crystal structure was in the orthorhombic with Pmmm space group with the ratio c/a were 3.0, 4.0, 5.0 and 6.0 for Y123, Y134, Y145 and Y156, respectively. The oxygen content was characterized by Iodometric titration. The ( Cu 3+/ Cu 2+ and Oxygen content) were (0.28, 6.83), (0.19, 8.81), (0.13, 10.79), (0.16, 12.92) of Y123, Y134, Y145, Y156, respectively. We also found that the increasing of sintering temperature has reduced the oxygen content and the critical temperature of all samples.