PUB - Publikationen an der Universität Bielefeld

The dependences of magnetic field penetration depth at zero temperature lambda(0), microwave surface resistance R(s) and pi -band energy gap at zero temperature Delta(pi)(0) on the normal-state resistivity fight above the critical, rho(0), were studied for MgB(2) thin films prepared by different temperature. techniques by employing a sapphire resonator technique. We found that the zero-temperature penetration depth lambda(0) data could be well fitted by lambda(L)(1 + xi(0)/l)(1/2) yielding a London penetration depth lambda(L) of 34.5 nm, where xi(0) is the coherence length, and l is the mean free path determined from rho(0). The surface resistance R(s) at 15 and 20 K increases roughly linearly with rho(0). The observed increase of Delta(pi)(0) with rho(0) and the decrease of T(c) indicate the expected effects of interband impurity scattering within an extended BCS approach. The low values of R(s) and lambda(0) in conjunction with the large coherence length for epitaxial films are potentially attractive for applications in electronics and microwave technology.