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arXiv · 1710.10672

Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films

H. Zhang·N. Gauquelin·C. McMahon·D. G. Hawthorn·G. A. Botton·J. Y. T. Wei
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Abstract

It is known that solid-state reaction in high-pressure oxygen can stabilize high-oxidation phases of Y-Ba-Cu-O superconductors in powder form. We extend this superoxygenation concept of synthesis to thin films which, due to their large surface-to-volume ratio, are more reactive thermodynamically. Epitaxial thin films of $\rm{YBa_2Cu_3O_{7-\delta}}$ grown by pulsed laser deposition are annealed at up to 700 atm O$_2$ and 900$^\circ$C, in conjunction with Cu enrichment by solid-state diffusion. The films show clear formation of $\rm{Y_2Ba_4Cu_7O_{15-\delta}}$ and $\rm{Y_2Ba_4Cu_8O_{16}}$ as well as regions of $\rm{YBa_2Cu_5O_{9-\delta}}$ and YBa$_2$Cu$_6$O$_{10-\delta}$ phases, according to scanning transmission electron microscopy, x-ray diffraction and x-ray absorption spectroscopy. Similarly annealed $\rm{YBa_2Cu_3O_{7-\delta}}$ powders show no phase conversion. Our results demonstrate a novel route of synthesis towards discovering more complex phases of cuprates and other superconducting oxides.

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H. Zhang, N. Gauquelin, C. McMahon, D. G. Hawthorn, G. A. Botton, J. Y. T. Wei. 2017-10-29. Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films. https://doi.org/10.1103/physrevmaterials.2.033803

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