Phase transformation in ultrathin Y-Ba-Cu-O films by high-pressure oxygen annealing
Abstract
To examine the thermodynamic phase stability of Y-Ba-Cu-O superconductors in ultrathin film form, we study the effects of high-pressure oxygen annealing and Cu enrichment on YBa2Cu3O7-δ films ranging from 8 nm to 15 nm in thickness. The films are grown epitaxially on SrTiO3 substrates by pulsed laser-ablated deposition, and post-annealed in 475 atm of oxygen at 800∘C while subjected to varying concentrations of excess CuO. X-ray diffraction (XRD) on the annealed films shows evidence for suppression of YBa2Cu3O7-δ and formation of Y2Ba4Cu8O16. This structural transformation towards a higher-oxidation phase is expectedly correlated with film thinness and Cu enrichment.
- Publication:
-
International Journal of Modern Physics B
- Pub Date:
- October 2017
- DOI:
- 10.1142/S0217979217450102
- Bibcode:
- 2017IJMPB..3145010Z
- Keywords:
-
- YBCO;
- cuprate;
- superconductivity;
- thin-films;
- pulsed laser-ablated deposition;
- phase conversion;
- high-pressure oxygen