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Transmission electron microscopic studies on growth mechanism of YBa2Cu3O7−y films formed by advanced trifluoroacetates metalorganic deposition process

Published online by Cambridge University Press:  31 January 2011

J. Matsuda ,
K. Nakaoka ,
T. Izumi ,
Y. Yamada  and
Y. Shiohara
J. Matsuda*
Affiliation:
Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), Koto-ku, Tokyo 135-0062, Japan
K. Nakaoka
Affiliation:
Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), Koto-ku, Tokyo 135-0062, Japan
T. Izumi
Affiliation:
Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), Koto-ku, Tokyo 135-0062, Japan
Y. Yamada
Affiliation:
Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), Koto-ku, Tokyo 135-0062, Japan
Y. Shiohara
Affiliation:
Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), Koto-ku, Tokyo 135-0062, Japan
*
a)Address all correspondence to this author. e-mail: junko.matsuda@aist.go.jp Present address: National Institute of Advanced Industrial Science and Technology (AIST), Energy Technology Research Institute, Tsukuba, Ibaraki 305-8565, Japan
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Abstract

Microstructure evolution of YBa2Cu3O7−y (YBCO) films during the two heat-treatments in the advanced trifluoroacetates metalorganic deposition (TFA-MOD) process has been investigated by means of transmission electron microscopy. In the calcination process, precursor films including nanopores were formed through the shrinkage of the film after a remarkable increase of the thickness due to the thermal decomposition of metalorganic salts in the starting solution. During the crystallization process, the densification and shrinkage of the film occurred after agglomeration of nanopores and coarsening of unreacted phase particles such as Y2Cu2O5, CuO, and Ba–O–F in the precursor films. The YBCO films were then epitaxially grown with the remaining unreacted phase particles in the film, finally pores were generated again by a reaction of these unreacted particles to form YBCO accompanied by the volume reduction. It is important to control the densification of precursor films and coarsening of the unreacted phase particles in the crystallization process, to fabricate YBCO final films with fine crystallinity and high critical current values.

Keywords

Metalorganic depositionSuperconductingTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 23 , Issue 12: Biomimetic and Bio-enabled Materials Science and Engineering , December 2008 , pp. 3353 - 3362
Copyright
Copyright © Materials Research Society 2008

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References

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