Tunneling spectroscopy and magnetization measurements of the superconducting properties of MgB<inf>2</inf>

Cryogenic scanning tunneling microscopy and magnetization measurements were used to study the superconducting properties of MgB2. The magnetization measurements show a sharp superconductor transition at Tc = 39 K, in agreement with previous works. The tunneling spectra exhibit BCS-like gap structures, with gap parameters in the range of 5 to 7meV, yielding a ratio of 2Δ/kBTc ∼ 3 - 4. This suggests that MgB2 is a conventional BCS s-wave superconductor, either in the weak-coupling or in the "intermediate-coupling" regime.