Synthesis and Processing of Doped Hg1Ba2Ca2Cu3Oy Superconductors
Detailed studies on the synthesis and processing of bulk (Hg,A)Ba2Ca2Cu3Oy (A=Bi, Pb) were conducted to understand the role of heat treatment, precursor phase assembly, and Hg-pressure during synthesis. An additional lower temperature annealing stage after high temperature reaction is shown to improve the microstructural characteristics of Hg1223 samples. BaCaCuO precursor powders containing free CaO allows formation of liquid phase and assists in grain growth and texture development. Control of Hg-pressure during the reaction by using an external Hg-source, in sealed tubes, improves the density of Hg1223 products. Chemical nature of external Hg-source changes Hg-pressure and influences melting characteristics and grain growth. CaHgO2 is shown to be a very effective external Hg-source for producing dense Hg1223 materials with improved grain growth and texture. Phase purity and microstructural characteristics are correlated with high field magnetization measurements.
KeywordsPrecursor Powder Seal Tube Porous Microstructure Wide Hysteresis National High Magnetic Field Laboratory
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- 3.K. Yamaura, J. L. Shimoyama, S. Hahakura, Z. Hiroi, M. Takano, and K. Kishio, Physica C 216: 6 (1995)Google Scholar
- 6.K. Isawa, A. T. Yamamoto, M. Itoh, S. Adchi, and H. Yamauchi, Appl. Phys. Lett. 65: 2105 (1994).Google Scholar
- 8.P. V. P. S. S. Sastry, K. M. Amm, D. C. Knoll, J. Schwartz, submitted to Journal of Superconductivity (1997).Google Scholar
- 9.K. M. Amm, P. V. P. S. S. Sastry, D. C. Knoll, J. Schwartz, submitted to Journal of Superconductivity (1997).Google Scholar