Growth of thick chemical solution derived pyrochlore La2Zr2O7 buffer layers for YBa2Cu3O7−x coated conductors

Knoth, Kerstin; Hühne, Ruben; Oswald, Steffen; Molina, Leopoldo; Eibl, O.; Schultz, L.; Holzäpfel, B.

doi:10.1016/j.tsf.2007.08.130

Cited by 48 publications

(30 citation statements)

References 26 publications

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“…They interpreted the crystal structure as pyrochlore, even if there was no visible evidence of (111) planes in the diffraction pattern. 9 In some cases, diffraction rings appear showing a local poor texture, which could not be detected by XRD. They established nanovoids as a typical feature for MOD-grown LZO buffer layers.…”

Section: B Lzo Obtained By Mocvd On Lao Single Crystalmentioning

confidence: 99%

High-resolution transmission electron microscopy observations of La₂Zr₂O₇ thin layers on LaAlO₃ obtained by chemical methods

et al. 2009

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La 2 Zr 2 O 7 (LZO) films have been grown by metalorganic decomposition (MOD) to be used as buffer layers for coated conductors. LZO can crystallize into two similar structures: fluorite or pyrochlore. Coated conductor application focuses on pyrochlore structure because it is a good barrier against oxygen diffusion. Classical x-ray diffraction is not able to separate the contribution of these two structures. Transmission electron microscopy and high-resolution transmission electron microscopy were used to determine the local distribution of these two phases in epitaxial LZO layers grown on LaAlO 3 . A characteristic feature of LZO thin films deposited by MOD is the formation of nanovoids in an almost single-crystal structure of LZO pyrochlore phase. For comparison, LZO layers deposited by metalorganic chemical vapor deposition were also studied. In this last case, the film is compact without voids and the structure corresponds to pyrochlore phase. Thus, the formation of nanovoids is a characteristic feature of MOD grown films.

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Section: B Lzo Obtained By Mocvd On Lao Single Crystalmentioning

confidence: 99%

High-resolution transmission electron microscopy observations of La₂Zr₂O₇ thin layers on LaAlO₃ obtained by chemical methods

et al. 2009

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“…A simple low cost architecture obtained by all-chemical routes consisting in YBCO MOCVD /La 2 Zr 2 O 7MOD /NiW RABiTS (MOCVD= Metalorganic Chemical Vapor Deposition, MOD= Metalorganic Decomposition) has been already validated in a previous work [4]. La 2 Zr 2 O 7 (LZO) buffer layers grown by MOD have been also tested in other architecture where YBCO was deposited by other methods like PLD [5] or MOD [6] The role of the buffer layer is double: to ensure the texture transmission from the texture substrates to the superconducting layer with a good lattice matching, and to protect the metallic substrate against oxidation. Pyrochlore LZO behaves as a buffer layer in this architecture because its lattice parameters match those of YBCO (|(ε YBCO -ε LZO )/ε LZO | = 1.05%), and also because it provides a good barrier against O 2 diffusion [7].…”

Section: Introductionmentioning

confidence: 99%

Effect of the annealing process on the microstructure of La2Zr2O7 thin layers epitaxially grown on LaAlO3 by metalorganic decomposition

Jiménez¹,

Caroff²,

Rapenne³

et al. 2009

Journal of Crystal Growth

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were varied to establish their influence on the microstructure of the LZO layers. XRD and TEM were used for sample characterisation. The epitaxial pyrochlore phase was obtained for annealing temperatures higher that 850°C whatever the other annealing conditions. However, the film microstructure, in particular, nanovoids shape and size, is strongly dependent on heating ramp and pressure during annealing. When using low heating ramp, percolation of voids creates diffusion channels for oxygen which are detrimental for the substrate protection during coated conductor fabrication. From this point of view high heating rates are more adapted to the growth of LZO layers.

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“…In recent years, a great deal of effort has been invested in studying growth behavior and the preparation of thick film in coated conductors, which are multi-layer composite materials composed of metal substrate/buffer layer/superconducting layer/protective layer, in order to guarantee a sufficient barrier function against metal and oxygen diffusion as well as obtain high-quality CC tape [4,5]. However, crack formation, rough surface and degraded bi-axial texture become the main challenge to the growth of a thick oxide film on textured substrate.…”

Section: Introductionmentioning

confidence: 99%

“…However, the existence of residual carbon, which originates possibly from a not completely decomposition of organic compounds, has a negative influence on the epitaxial growth of oxide film. The accumulation of residual carbon at the grain boundary can even lead to crack formation on the surface of buffer layer [4]. Sever macro-cracks are easily found on surface of the buffer layer although the content of residual carbon could be decreased to a certain degree by element doping, nitrate precursor adoption and oxidation gas selection [10,11].…”

Section: Introductionmentioning

confidence: 99%

Growth of thick MOD-derived CeO2−x buffer layer with less residual carbon for coated conductors

Wang

Cao

Wang

et al. 2015

J Mater Sci: Mater Electron

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120 nm thick CeO 2-x buffer layer with less residual carbon has been prepared on biaxially textured NiW substrate using a newly developed heat-treatment route by a metal organic deposition approach. The thickness enhancement of CeO 2-x buffer layer was achieved by multiple coatings. The residual carbon removal in CeO 2-x buffer layer was realized by introducing CO 2 into annealing atmosphere at the post-annealed step. Various characteristic methods, including X-ray diffraction, X-ray photoelectron spectra, emission scanning electron microscopy and atomic force microscopy analyses techniques have been applied to investigate the performance of CeO 2-x film. The results show that thick high-quality textured CeO 2-x film with smooth and crack-free surface has been produced at annealing temperature below 1000°C. Furthermore, the atomic concentration of C in such thick CeO 2-x buffer layer prepared using the postannealed step by introducing CO 2 into annealing atmosphere is obviously less than that in CeO 2-x film fabricated in reducing atmosphere of Ar-4 % H 2 . In addition, the introduction of CO 2 into post-annealing step is helpful to the decrease of oxygen vacancy defects in CeO 2-x film, which can suppress the generation of cracks in film. It suggests that CeO 2-x film fabricated by the newly developed heat-treatment route is proved to be a strong candidate as a buffer layer used for the further growth of the oxide film in coated conductors.

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Growth of thick chemical solution derived pyrochlore La2Zr2O7 buffer layers for YBa2Cu3O7−x coated conductors

Cited by 48 publications

References 26 publications

High-resolution transmission electron microscopy observations of La₂Zr₂O₇ thin layers on LaAlO₃ obtained by chemical methods

High-resolution transmission electron microscopy observations of La₂Zr₂O₇ thin layers on LaAlO₃ obtained by chemical methods

Effect of the annealing process on the microstructure of La2Zr2O7 thin layers epitaxially grown on LaAlO3 by metalorganic decomposition

Growth of thick MOD-derived CeO2−x buffer layer with less residual carbon for coated conductors

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Growth of thick chemical solution derived pyrochlore La2Zr2O7 buffer layers for YBa2Cu3O7−x coated conductors

Cited by 48 publications

References 26 publications

High-resolution transmission electron microscopy observations of La2Zr2O7 thin layers on LaAlO3 obtained by chemical methods

High-resolution transmission electron microscopy observations of La2Zr2O7 thin layers on LaAlO3 obtained by chemical methods

Effect of the annealing process on the microstructure of La2Zr2O7 thin layers epitaxially grown on LaAlO3 by metalorganic decomposition

Growth of thick MOD-derived CeO2−x buffer layer with less residual carbon for coated conductors

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High-resolution transmission electron microscopy observations of La₂Zr₂O₇ thin layers on LaAlO₃ obtained by chemical methods

High-resolution transmission electron microscopy observations of La₂Zr₂O₇ thin layers on LaAlO₃ obtained by chemical methods