A more accurate method to measure the oxygen content in YBa₂Cu₃O_y superconductors

Abstract

The copper (Cu) valence greatly influences the transition temperature (T_c) 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 La_2−xSr_xCuO₄ and YBa₂Cu₃O_y (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.