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, T. J. Marks

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


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 (US)
Pages (from-to)146-154
Number of pages9
JournalPhysica C: Superconductivity and its applications
Issue number1-2
StatePublished - Feb 10 1997


  • Microstructure
  • TlBaCaCuO superconducting thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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