Cryogenically cleaved surfaces of epitaxially grown Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O films were studied using the film-edge junction technique. The junctions were analized based on a simple junction model. The junction qualities were degraded mainly due to the leaky tunneling barrier and the exposed normal material at the surface of the oxide superconductors. The gap energies were found to have the gap closing temperatures. The linearity between Tc (Δ=0) and Δ(0) was found to be better than that between Tc(R=0) and Δ(0). Such linearity was found in the Tc range between 40 K and 80 K. For Y-Ba-Ca-O and Bi-Sr-Ca-Cu-O samples, the normalized gap energy 2Δ(0)/kBTc that associated with the peak voltage value in the σ-V characteristics was about 6 (±0.2) in the direction of the Cu-O plane, in contrast to a smaller normalized gap energy found in the c-plane cleaved junction.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering