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 YBa2Cu3O7−δ grown by pulsed laser deposition are annealed at up to 700 atm O2 and 900∘C, in conjunction with Cu enrichment by solid-state diffusion. The films show clear formation of Y2Ba4Cu7O15−δ and Y2Ba4Cu8O16 as well as regions of YBa2Cu5O9−δ and YBa2Cu6O10−δ phases, according to scanning transmission electron microscopy, x-ray diffraction and x-ray absorption spectroscopy. Similarly annealed YBa2Cu3O7−δ powders show no phase conversion. Our results demonstrate a novel route of synthesis towards discovering more complex phases of cuprates and other superconducting oxides.
@article{arxiv.1710.10672,
title = {Synthesis of high-oxidation Y-Ba-Cu-O phases in superoxygenated thin films},
author = {H. Zhang and N. Gauquelin and C. McMahon and D. G. Hawthorn and G. A. Botton and J. Y. T. Wei},
journal= {arXiv preprint arXiv:1710.10672},
year = {2018}
}
Comments
Accepted for publication in Physical Review Materials