Superconducting Material Diagnostics using a Scanning Near-Field Microwave Microscope

TL;DR

This paper introduces a scanning near-field microwave microscope capable of imaging superconducting materials at micron-scale resolution, providing quantitative data on properties like sheet resistance and critical temperature.

Contribution

The work presents a novel microwave microscopy technique for detailed, quantitative imaging of superconducting materials at micron-scale resolution.

Findings

Imaging of sheet resistance in superconducting thin films

Spatially resolved measurements of critical temperature (Tc)

Quantitative imaging of surface properties

Abstract

We have developed scanning near-field microwave microscopes which can image electrodynamic properties of superconducting materials on length scales down 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 YBa2Cu3O7-d thin film wafer, images of bulk Nb surfaces, and spatially resolved measurements of Tc of a YBa2Cu3O7-d thin film. We also discuss some of the limitations of the microscope and conclude with a summary of its present capabilities.