Imaging magnetic fields

The scanning superconducting quantum interference devices (SQUID) microscope operations and applications are discussed. Scanning SQUID microscopes (SSMs) are instruments that can image magnetic fields at the surface of samples with a sensitivity at unprecedented levels. They can sense fields of less than a hundred picoteslas, currents of a few nanometers, and magnetic moments of a few Bohr magnetons. The applications of SSMs in the study of superconductivity are discussed.