Determination of Cu2+ and Cu3+ by titration in Y134 and Y145 superconductor

Abstract

The Y123 (YBa2Cu3O7-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 CuO2 planes. That the oxygen content has the relation on the ratio of Cu2+and Cu3+. In this paper, we interested in Y134 (YBa3Cu4O9-y) and Y145 (YBa4Cu5O11-y) superconductor found in 2010. To investigate the effect of Ag2O addition on some properties of Y134 and Y145 superconductor, these superconductors doped with Ag2O 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 Tc onset at 97 K and 96 K, the lowest critical temperature was found in pure sample with Tc 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 Cu3+/ Cu2+ ratio of Y134 were high amount on 0.15 and 0.14 at 0.15-doped and 0.1-doped sample. The Cu3+/ Cu2+ ratio of Y145 were high amount on 0.10-doped sample which equal to 0.10. Our results mean that the higher Cu3+/ Cu2+ ratio, the higher critical temperature found.