Superconducting material diagnostics using a scanning near-field microwave microscope

We have developed scanning near-field microwave microscopes which can image electrodynamic properties of superconducting materials on length scales down to about 2 /spl mu/m. The microscopes are capable of quantitative imaging of sheet resistance of thin films, and surface topography. We demonstrate the utility of the microscopes through images of the sheet resistance of a YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin film wafer, images of bulk Nb surfaces, and spatially resolved measurements of T/sub c/ of a YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin film. We also discuss some of the limitations of the microscope and conclude with a summary of its present capabilities.