Fabrication and tunneling measurements of YBa/sub 2/Cu/sub 3/O/sub x//CaF/sub 2//Nb thin film tunnel junctions

Author

Tsuge, H. ; Matsukura, N.

Author_Institution

NEC Corp., Ibaraki, Japan

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

2401

Lastpage

2404

Abstract

The heteroepitaxial growth of YBa/sub 2/Cu/sub 3/O/sub x/(YBCO)/CaF/sub 2/ has been studied and this structure has been applied to tunnel junctions. The CaF/sub 2/ thin film were epitaxially grown with [111] orientation on YBCO[110] films. The tunneling measurements of YBCO[110]/CaF/sub 2//Nb junctions exhibited that the differential conductance curves have pronounced gap-like structures with sharp peaks at the energy gap edge. The temperature dependence of the energy gap was well fitted to the scaled BCS curve. The 2 Delta /kTc of about eight was derived from the energy gap of 15 meV and T/sub c/ of 45 K obtained by the fitting. This 2 Delta /kTc value was consistent with the infrared reflectivity data reported for the direction parallel to the Cu-O planes.<>

Keywords

Auger effect; BCS theory; X-ray diffraction examination of materials; X-ray photoelectron spectra; barium compounds; calcium compounds; electron beam deposition; energy gap; high-temperature superconductors; niobium; reflection high energy electron diffraction; reflectivity; superconducting epitaxial layers; superconducting junction devices; superconductive tunnelling; yttrium compounds; 45 K; Auger electron spectroscopy; RHEED; X-ray diffraction; X-ray photoemission spectroscopy; YBa/sub 2/Cu/sub 3/O/sub x/-CaF/sub 2/-Nb tunnel junction; [110] surface; [111] surface; differential conductance curves; electron beam guns; energy gap edge; heteroepitaxial growth; infrared reflectivity; reactive coevaporation system; scaled BCS curve; temperature dependence; thin film tunnel junctions; Electrons; Epitaxial growth; Fabrication; Niobium; Substrates; Superconductivity; Temperature; Transistors; Tunneling; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233418

Filename

233418