Scanning squid microscopy

The scanning SQUID microscope (SSM) is a powerful tool for imaging magnetic fields above sample surfaces. It has the advantage of high sensitivity;md bandwidth and the disadvantages of relatively modest spatial resolution and the requirement of a cooled SQUID sensor. We describe the various implemen tations of this type of instrument and discuss a number of applications, in cluding magnetic imaging of short circuits in integrated circuits, corrosio n currents in aluminum, and trapped flux in superconductors.