We investigated the interface microstructure of sandwich-type MgB 2/Al-AlOx/MgB2 Josephson tunnel junctions by cross-sectional transmission electron microscopy (TEM) in order to clarify the non-idealities in the junction characteristics. The results indicate that there are poor-crystalline MgB2 layers and/or amorphous Mg-B composite layers of a few nanometers between the AlOx barrier and upper MgB2 layer. The poor-crystalline upper Mg-B layers seem to behave as normal metal or deteriorated superconducting layers, which may be the principal reason for all non-idealities of our MgB2/Al-A1Ox-/ MgB2 junctions.
|Journal||Japanese Journal of Applied Physics, Part 2: Letters|
|Publication status||Published - 2007 Apr 13|
- Josephson junctions
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)