A more accurate method to measure the oxygen content in YBa₂Cu₃O<i>_y</i> superconductors

Abstract

The copper (Cu) valence greatly influences the transition temperature (Tc) in cuprate superconductors. According to the charge neutralization rule, the Cu valence is calculated from the oxygen content. Previously, we developed the dissolved oxygen (DO) method as a novel oxygen measurement method for La2−xSrxCuO4 and YBa2Cu3Oy (YBCO) using a new DO sensor. The measurement time of the DO method is about one-third that of the standard iodometric method, but the difference in the measured Cu valence for YBCO is 0.039. Herein we report that a more accurate method, which combines the dissolved chlorine method and the corrected DO method, improves this difference to 0.013.