High frequency electrodynamic measurements are used as sensitive probes of the Meissner and mixed states of superconductors. Measurements of the surface resistance and penetration depth at several frequencies in the MHz and GHz ranges will be carried out as a function of temperature and magnetic field. The results will be analyzed to extract information regarding the dynamics of the condensate, quasiparticles and vortices, and will be compared with fundamental models. The materials which will be studied are several of the high and low Tc superconductors. The vortices will be paramaterized and the resulting measurements will be used to test theories of vortex formation, melting, vortex glass, and other thermodynamic states %%% This project explores the response of high temperature superconductors to alternating electric and magnetic fields. The results are expected to be important for both fundamental understanding and for applications of superconducting devices at high frequencies.
