Electron-tunneling measurements on the new superconductor MgB2 with Tc = 39 K have been carried out using a break-junction technique. The measurements reveal the largest gap value of 2Δ = 17-19 meV at 4.2 K. This value leads to the ratio 2Δ/kBTc = 5-5.6, indicating the strong-coupling superconductivity. We have also observed the reproducible gap values of 2Δ ≅ 4-4.5 meV and 7-9 meV. The smallest gap exists even beyond 30 K. We will discuss the implication of the data.
- Break junction
- Tunneling spectroscopy
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering