The dependences of magnetic field penetration depth at zero temperature λ(0), microwave surface resistance Rs and π-band energy gap at zero temperature Δπ (0) on the normal-state resistivity right above the critical temperature, ρ0, were studied for MgB 2 thin films prepared by different techniques by employing a sapphire resonator technique. We found that the zero-temperature penetration depth λ(0) data could be well fitted by λL (1 + ξ0/l)1/2 yielding a London penetration depth λL of 34.5 nm, where ξ0 is the coherence length, and l is the mean free path determined from ρ0. The surface resistance Rs at 15 and 20 K increases roughly linearly with ρ0. The observed increase of Δπ (0) with ρ 0 and the decrease of Tc indicate the expected effects of interbank impurity scattering within an extended BCS approach. The low values of Rs and γ(0) in conjunction with the large coherence length for epitaxial films are potentially attractive for applications in electronics and microwave technology.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Condensed Matter Physics
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry