Phase diagram for 1/2 Yb 2O 3BaOCuO

• Published in: Physica. C, Superconductivity Vol. 288; no. 3; pp. 151 - 157
• Main Authors: Oniyama, Emmanuel, Wahlbeck, Phillip G., Peterson, Dean E., Yates Coulter, J., Peterson, Eric J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1997
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/S0921-4534(97)01569-4

The phase diagram of the 1/2 Yb 2O 3BaOCuO system has been studied in oxygen at 935°C. An inert gas glove box was used for sample manipulation and storage to avoid problems caused by reactions of BaO-rich samples with atmospheric CO 2 and H 2O. Ternary phases prepared and identified were YbBa 2Cu 3O x (Yb-123), YbBa 4Cu 3O y (Yb-143), YbBa 6Cu 3O z (Yb-163), and Yb 2BaCuO 5 (Yb-211). Compositions on and around the tie line between Yb-211 and BaCuO 2 were also prepared and studied. X-ray diffracton measurements and differential thermal analyses were carried out to identify phases present. Results indicated that the 1/2 Yb 2O 3BaOCuO system is very similar to the 1/2 Y 2O 3BaOCuO system with the same ternary phases and with no extensive solid solution. The Yb-123 phase is the only superconducting phase in the system with an observed T c of 90 ± K. The Yb-163 phase was observed to react rapidly with ambient air.