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High temperature X-ray diffraction studies of the decomposition mechanism of YBa2Cu3O7−δ at an oxygen partial pressure less than 10 Pa

Published online by Cambridge University Press:  10 January 2013

W. Pitschke
Affiliation:
Institut für Festkörper und Werkstofforschung Dresden e.V., Postfach, D-01171 Dresden, Germany
W. Bieger
Affiliation:
Institut für Festkörper und Werkstofforschung Dresden e.V., Postfach, D-01171 Dresden, Germany
G. Krabbes
Affiliation:
Institut für Festkörper und Werkstofforschung Dresden e.V., Postfach, D-01171 Dresden, Germany

Abstract

The crystallographic data of YBa2Cu3O7−δ, Y2BaCuO5, BaCu2O2, and YBa4Cu3O9 at high temperatures and p(O2)<10 Pa have been derived on the basis of HT-XRD measurements. Whereas Y2BaCuO5 expands nearly isotropically, YBa2Cu3O7−δ and BaCu2O2 show anisotropic expansions. Furthermore, the first decomposition step of the considered compounds at p(O2)<10 Pa was observed. BaCu2O2 melts congruently at T ≍ 1273 K and Y2BaCuO5 decomposes via a peritectic reaction into Y2O3, Y2BaO4 and melts at T ≍ 1323 K. A solid-state reaction into Y2BaCuO5 and BaCu2O2 was indicated for YBa2Cu3O7−δ at T ≍ 1123 K. Because YBa4Cu3O9 becomes unstable at T ≍ 1123 K, this compound cannot be formed by the primary decomposition reaction of YBa2Cu3O7−δ

Type
Research Article
Copyright
Copyright © Cambridge University Press 1995

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References

Aselage, T., and Keefer, K. (1988). “Liquid relations in Y–Ba–Cu oxidesJ. Mater. Res. 3, 12791291.CrossRefGoogle Scholar
Bieger, W., Fischer, K., Frenzel, Ch., Krabbes, G., Pitschke, W., Risse, G., Schubert, M., and Wiesner, U. (1993). “Decomposition mechanism of YBa2Cu3Ox at various oxygen partial pressures and its influence on the microstructure of YBCO/Ag composites,” in Applied Superconductivity, edited by Freyhardt, H. C. (DGM-Informationsgesellschaft-Verlag, Oberursel), pp. 239243.Google Scholar
Brown, N. E., Swapp, S. M., Bennett, C. L., and Navrotsky, A. (1993). “High-Temperature X-Ray Diffraction: Solutions to Uncertainties in Temperature and Sample Position,” J. Appl. Cryst. 26, 7781.CrossRefGoogle Scholar
Hase, T., Kita, R., Kawaguchi, K., Koga, T., and Morishita, T. (1993). “Differences in Effects of Oxygen Partial Pressure on YBa2Cu3O7−x Growth between in situ and ex situ Processes,” Physica C 207, 5864.CrossRefGoogle Scholar
Klockow, X., and Eysel, X. (1988). “Standard X-Ray Diffraction Powder Pattern of BaCu2O2,” JCPDS Grant-in-Aid Report, Newtown Square, PA, International Centre for Diffraction Data.Google Scholar
Krabbes, G., Bieger, W., Wiesner, U., Ritschel, M., and Teresiak, A. (1993). “Isothermal sections and Primary Crystallization in the Quasiternary YO1.5-BaO-CuOx, System at p(O2) = 0.21*105Pa,” J. Solid State Chem. 103, 420432.CrossRefGoogle Scholar
Krabbes, G., Wiesner, U., Pitschke, W., and Bieger, W. (1994). To be published in Physica C.Google Scholar
Kwestroo, W., van Hal, H. A. M., and Langereis, C. (1974). “Compounds in the System BaO-Y2O3,” Mater. Res. Bull. 9, 16311638.CrossRefGoogle Scholar
Lindemer, T. B., Washburn, F. A., McDougall, C. S., Feenstra, R., and Cavin, O. B. (1991). “Decomposition of YBa2Cu3O7−x, and YBa2Cu4O8 for P(O2 )≤ O.1 MPa,” Physica C 178, 93101.CrossRefGoogle Scholar
Martin, K., and McCarthy, G. (1989). “Standard X-Ray Diffraction Powder Pattern of Y2O3,” JCPDS Grant-in-Aid Report, Swarthmore, PA, International Centre for Diffraction Data.Google Scholar
Mattern, N., Pitschke, W., Danzig, A., and Doyle, S. (1994). “X-ray diffraction at high temperatures,” Fres. J. Anal. Chem. 349, 9196.CrossRefGoogle Scholar
Powder Diffraction File (1991). JCPDS-International Centre for Diffraction Data, Newtown Square Corporate Campus, 12 Campus Boulevard, Newtown Square, PA 19073-3273 USA.Google Scholar
Rodriguez, M. A., Snyder, R. L., Chen, B. J., Metheis, D. P., Misture, S. T., Frechette, V. D., Zorn, G., Gobel, H. E., and Seebacher, B. (1993). “The high temperature reactions of YBa2Cu3O7−δPhysica C 206, 4350.CrossRefGoogle Scholar
Schreiner, W. N., and Jenkins, R. (1983). “Profile Fitting for Quantitative Analysis in X-ray Powder Diffraction,” Adv. X-ray Anal. 26, 141143.Google Scholar
Wilson, A. J. C. (1950). “Geiger-counter X-ray spectrometer—Influence of size and absorption coefficient of specimen on position and shape of powder diffraction maxima,” J. Sci. Instrum. 27, 321325.CrossRefGoogle Scholar
Wong-Ng, W., McMurdie, H. F., Paretzkin, B., Zhang, Y., Davis, K. L. Hubbard, C. R., and Dragoo, A. (1987). “Standard X-Ray Diffractions Patterns of Sixteen Ceramic Phases,” Powder Diffr. 2, 191201.CrossRefGoogle Scholar