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Title: Secondary phases in (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxial thin films

Abstract

The composition and orientation of secondary phases in epitaxial (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films [where R is a rare earth element] grown by MOCVD were investigated by HREM, XRD, SEM, and other techniques. The observed secondary phases often did not correspond to those expected from equilibrium phase diagrams of bulk R--Ba--Cu--O systems. No evidence was found for the presence of R{sub 2}BaCuO{sub 5} or BaCuO{sub 2}, which are the equilibrium phases with bulk RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. In contrast, inclusions of well-oriented R{sub 2}CuO{sub 4}(R = Gd), R{sub 2}O{sub 3} (R = Lu, Ho, Y), R{sub 2}Cu{sub 2}O{sub 5}(R = Lu), Ba{sub 2}CuO{sub 3}, and BaCu{sub 3}O{sub 4} were observed, depending on the films' stoichiometry. It is concluded that the formation of coherent or semicoherent interfaces between embedded inclusions and the surrounding matrix is critical for a stabilization of otherwise nonequilibrium oxide phases in epitaxial films. The crystal structure of unstable-in-bulk cuprate BaCu{sub 3}O{sub 4} was determined using electron nanodiffraction of the films' cross sections.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Moscow State Univ. (RU)
OSTI Identifier:
20001168
Resource Type:
Journal Article
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 11; Journal Issue: 9; Other Information: PBD: Sep 1999; Journal ID: ISSN 0897-4756
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; RARE EARTH COMPOUNDS; BARIUM OXIDES; COPPER OXIDES; THIN FILMS; PHASE DIAGRAMS; CRYSTAL STRUCTURE

Citation Formats

Samoylenkov, S.V., Gorbenko, O.Y., Graboy, I.E., Kaul, A.R., Zandbergen, H.W., and Connolly, E. Secondary phases in (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxial thin films. United States: N. p., 1999. Web. doi:10.1021/cm991016v.
Samoylenkov, S.V., Gorbenko, O.Y., Graboy, I.E., Kaul, A.R., Zandbergen, H.W., & Connolly, E. Secondary phases in (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxial thin films. United States. doi:10.1021/cm991016v.
Samoylenkov, S.V., Gorbenko, O.Y., Graboy, I.E., Kaul, A.R., Zandbergen, H.W., and Connolly, E. Wed . "Secondary phases in (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxial thin films". United States. doi:10.1021/cm991016v.
@article{osti_20001168,
title = {Secondary phases in (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxial thin films},
author = {Samoylenkov, S.V. and Gorbenko, O.Y. and Graboy, I.E. and Kaul, A.R. and Zandbergen, H.W. and Connolly, E.},
abstractNote = {The composition and orientation of secondary phases in epitaxial (001)RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films [where R is a rare earth element] grown by MOCVD were investigated by HREM, XRD, SEM, and other techniques. The observed secondary phases often did not correspond to those expected from equilibrium phase diagrams of bulk R--Ba--Cu--O systems. No evidence was found for the presence of R{sub 2}BaCuO{sub 5} or BaCuO{sub 2}, which are the equilibrium phases with bulk RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. In contrast, inclusions of well-oriented R{sub 2}CuO{sub 4}(R = Gd), R{sub 2}O{sub 3} (R = Lu, Ho, Y), R{sub 2}Cu{sub 2}O{sub 5}(R = Lu), Ba{sub 2}CuO{sub 3}, and BaCu{sub 3}O{sub 4} were observed, depending on the films' stoichiometry. It is concluded that the formation of coherent or semicoherent interfaces between embedded inclusions and the surrounding matrix is critical for a stabilization of otherwise nonequilibrium oxide phases in epitaxial films. The crystal structure of unstable-in-bulk cuprate BaCu{sub 3}O{sub 4} was determined using electron nanodiffraction of the films' cross sections.},
doi = {10.1021/cm991016v},
journal = {Chemistry of Materials},
issn = {0897-4756},
number = 9,
volume = 11,
place = {United States},
year = {1999},
month = {9}
}