New structural aspects of Tl2Ba2CaCu2Oy epitaxial thin films grown by MOCVD on LaAlO3

X. F. Zhang, Y. S. Sung, D. J. Miller, B. J. Hinds, R. J. McNeely, D. L. Studebaker, Tobin J Marks

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Abstract

The microstructure of a Tl2Ba2CaCu2Oy (Tl-2212) superconducting thin film grown by metal-organic chemical vapor deposition (MOCVD) on a pseudo-cubic (001) LaAlO3 substrate has been examined by analytical transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). Over large regions, the film is epitaxial and Tl-2212 phase is found to be the major phase. The film/substrate interface is abrupt and smooth on the atomic scale but a strain-field is induced by the lattice mismatch between the film and the substrate. In addition to the intrinsic modulation structure of the Tl-2212 phase, a very different modulation structure has also been found. The space group for the Tl-2212 phase in this thin film was determined to be I4mm rather than I4/mmm as usually reported. The loss of the (001) mirror plane is attributed to a defective Tl-2212 structure in which a considerable amount of Tl vacancies and Tl disorder occurred inhomogeneously in Tl-O layers. The reason for the Tl-deficiency is discussed.

Original languageEnglish
Pages (from-to)146-154
Number of pages9
JournalPhysica C: Superconductivity and its Applications
Volume275
Issue number1-2
Publication statusPublished - Feb 10 1997

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Keywords

  • Microstructure
  • TlBaCaCuO superconducting thin film

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Zhang, X. F., Sung, Y. S., Miller, D. J., Hinds, B. J., McNeely, R. J., Studebaker, D. L., & Marks, T. J. (1997). New structural aspects of Tl2Ba2CaCu2Oy epitaxial thin films grown by MOCVD on LaAlO3. Physica C: Superconductivity and its Applications, 275(1-2), 146-154.