The grain boundaries (GB's) in the intermetallic superconductor MgB2, interestingly, do not show suppression of supercurrent density. This unexpected behavior has been investigated by a scanning tunneling microscopy/spectroscopy technique at atomic resolution. The GB in MgB2 is seen as an amorphous region extending from ∼50 to 200 Å and has a metallic character. This observation supports proximity coupling between the grains, which explains why supercurrent density does not degrade in this material. The results for another intermetallic superconductor YNi2B2C having GB's (average width ∼30 Å) that are quasi-insulating in nature have also been presented and compared with the former.
|Number of pages||3|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Mar 1 2002|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics