Superconducting material diagnostics using a scanning near-field microwavemicroscope

We have developed scanning near-field microwave microscopes which can image electrodynamic properties of superconducting materials on length scales do wn to about 2 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 YBa2 Cu3O7.delta thin film wafer, images of bulk Nb surfaces, and spatially reso lved measurements of T-c of a YBa2Cu3O7.delta thin film. We also discuss so me of the limitations of the microscope and conclude with a summary of its present capabilities.