VAPOR-PRESSURE SCANNING OF OXYGEN NONSTOICHIOMETRY IN YBA2CU3OY

Oxygen nonstoichiometry in high-T-c superconductor YBa2Cu3Oy was studi ed by vapor pressure measurements in a closed volume in the temperatur e range 673 to 1173 K and oxygen pressure up to 1 atm. P-T-X phase rel ationships were derived from the vapor pressure scanning of the solidu s surface. Analytical representation of isothermal, isobaric, and isop lethal (X(s) = const) sections of the P-T-X diagram is given. Partial thermodynamic functions of oxygen were calculated in the oxygen nonsto ichiometry range 6.30 to 6.85. (C) 1995 Academic Press, Inc.