Thermodynamics of YBa2Cu3Oz

✍ Scribed by P. Gerdanian; C. Picard; J.F. Marucco

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 566 KB
• Volume: 157
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(89)90485-1

✦ Synopsis

AG(O2 ) and AH(O2 ), respectively partial relative Gibbs free energy and enthalpy of 02 in YBa2Cu30~ have been measured with high precision at 500, 600 and 700 °C for 10-2< Po2/atm ~ 1. AG (O2) has been determined by means of the equilibrium method between oxide and N2-O2 mixtures using a thermobalance. AH(O2) has been measured by reaction microcalorimetry between oxide and N2-O 2 mixtures.

At the orthorhombic-to-tetragonal transition point, AG (O2) is continuous and AH(02) undergoes a 2-type discontinuity which is quite coherent with the interpretation of this phase transformation as an order-disorder transition.