Reproducible planar tunnel junctions based on high-quality YBa2Cu3O7 thin films are studied as a junction of crystallographic orientation. Using Pb as a counter-electrode, all junctions exhibit zero bias anomalies, the sign of which depends upon the crystallographic orientation of the film. For c-axis, or (001) films, in which the CuO2 planes are parallel to the junction surface, a 5 mV wide dip in the tunneling conductance, which is independent of applied magnetic field up to 5 T, is observed. Conversely, for the (103) and (100) orientations, in which the CuO2 plane points toward the junction surface, a peak in the tunneling conductance, which is strongly magnetic-field dependent, is observed. Analysis is performed in terms of spin-flip and Kondo-type scattering at the interface (Anderson and Applebaum theory).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering