Determination of Cu 2+ and Cu 3+ by titration in Y134 and Y145 superconductor

Abstract

The Y123 (YBa 2 Cu 3 O 7-y ) superconductor is the first high-temperature superconductor having critical temperature, higher than the boiling point of liquid nitrogen. The critical temperature of YBaCuO superconductor depends on the relative concentration of the oxygen within the CuO 2 planes. That the oxygen content has the relation on the ratio of Cu 2+ and Cu 3+ . In this paper, we interested in Y134 (YBa 3 Cu 4 O 9-y ) and Y145 (YBa 4 Cu 5 O 11-y ) superconductor found in 2010. To investigate the effect of Ag 2 O addition on some properties of Y134 and Y145 superconductor, these superconductors doped with Ag 2 O were synthesized by solid state reaction. The calcinations and sintering temperature were at 920 °C and annealing temperature was at 550 °C. The highest critical temperature was found in doped 0.1Ag sample with T c onset at 97 K and 96 K, the lowest critical temperature was found in pure sample with T c onset at 91 K and 95 K for Y134 and Y145, respectively. We found that the surface of Y134 and Y145 superconductor was improved by Ag adding on the porous structure. The Cu 3+ / Cu 2+ ratio of Y134 were high amount on 0.15 and 0.14 at 0.15-doped and 0.1-doped sample. The Cu 3+ / Cu 2+ ratio of Y145 were high amount on 0.10-doped sample which equal to 0.10. Our results mean that the higher Cu 3+ / Cu 2+ ratio, the higher critical temperature found. © 2018 Elsevier Ltd. All rights reserved.