Microwave surface resistance in superconductors with grain boundaries
arXiv:cond-mat/0501225
Abstract
Microwave-field distribution, dissipation, and surface impedance are theoretically investigated for superconductors with laminar grain boundaries (GBs). In the present theory we adopt the two-fluid model for intragrain transport current in the grains, and the Josephson-junction model for intergrain tunneling current across GBs. Results show that the surface resistance nonmonotonically depends on the critical current density at GB junctions, and for superconductors with GBs can be smaller than the surface resistance for ideal homogeneous superconductors without GBs.
6 pages, 1 figure, accepted for publication in Phys. Rev. B