Selective plasma oxidation of oxygen-deficient YBa2Cu 3O7-x

Akira Yoshida, Hirotaka Tamura, Kohtaroh Gotoh, Takeshi Imamura, Shinya Hasuo, Jun Akimitsu

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A selective plasma oxidation method was developed to make superconducting patterns in nonsuperconducting deoxygenated YBa2Cu3O 7-x (YBCO) films. Superconductor- nonsuperconductor-superconductor junctions were fabricated in oxygen-deficient c-axis-oriented polycrystalline YBCO films by selective plasma oxidation using Au/BaF2 oxidation masks. These devices displayed SNS-like or SIN-like nonlinear current-voltage relationships, depending on the device size and oxidation time. The oxygen penetration depth beneath the oxidation mask was estimated to be about 2 μm for the polycrystalline films. Oxygen supplied to 300-nm-thick films for 5 min changes its phase, determined from x-ray diffraction patterns, from tetragonal to orthorhombic I having a critical temperature of about 85 K. X-ray diffraction and magnetic susceptibility measurement showed that the plasma oxidation can supply oxygen to a deoxygenated 0.7×0.5×0.05 mm YBCO single crystal, changing the entire crystal from tetragonal to the orthorhombic II phase whose critical temperature is about 50 K. Four-probe resistance measurement of the plasma oxidized single crystal showed that the phase of the surface of the sample became orthorhombic I with the critical temperature of 84 K by plasma oxidation.

Original languageEnglish
Pages (from-to)7549-7555
Number of pages7
JournalJournal of Applied Physics
Volume73
Issue number11
DOIs
Publication statusPublished - Dec 1 1993
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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