Concentration of RE (Y, Pr, Sm, Gd, Dy, Yb) Elements in Liquid of Ba-Cu-O Liquid/REBa2Cu3O7−δ or RE2BaCuO5 Two Phase Region

Each solubility of Y, Yb, Dy, Pr and Sm for the Ba-Cu-O melt in air atmosphere was investigated by ICP measurement. The melt compositions were selected BaCu3O4 for Pr and Ba3Cu5O8 for other elements because these compositions were used to fabricate REBa2Cu3O7−δ (RE; rare earth) by the crystal pulling method. The measurements have been made in the temperature range from approximately 1223 K to about 1573 K. According to these results, the liquidus slope of 123 phase/liquid and 211 phase (110 phase in the case of the Pr system)/liquid was determined at each peritectic temperature. The solubility of Y for the Ba-Cu-O melt in different O2 partial pressures and P(O2)=2, 21.3, 101 kPa was measured. The decomposition temperature of the Y123 phase increased with increasing oxygen partial pressure. However, the effect of oxygen partial pressure for the Y concentration in the liquid at the temperature range of Y123+Liquid was relatively small. Furthermore, we estimate the enthalpy of dissolution of RE123, RE211 and Pr110 by a simple thermodynamic model with regular solution approximation.