Abstract
Effects of fluorine treatment of YBa2Cu3O7-x were investigated. The Tc was increased about 2 degrees by fleon treatment at 400°C. The Tc, however, was dropped about 2 degrees in a day of exposure in air at a room temperature into similar values for the sample without fleon treatment. The fluorine-doping to YBa2Cu3O7-x have also been examined, but did not yield any higher Tc phases. Since the doped fluorides were hydrolyzed by H2O contained in air at high temperature, the contents of fluorine in Y-Ba-Cu-O phase were gradually decreased during reaction, sintering, and/or annealing, and would become very small.
