2-DIMENSIONAL IMAGING OF THE RESISTIVE VOLTAGE CHANGES IN A SUPERCONDUCTOR CAUSED BY IRRADIATION WITH AN ELECTRON-BEAM

Scanning the surface of a current-carrying superconductor with an electron beam at temperatures below Tc provides a novel method for investigating structural inhomogeneities in the material. The resistive voltage changes caused by the electron irradiation can be used for modulating the brightness of the oscilloscope screen in a scanning electron microscope. In this way a two-dimensional image of the voltage changes can be obtained. We have performed such experiments at 4.2 K, using superconducting microbridges of lead. Here the inhomogeneous distribution of the transport current density can easily be visualized. The restrictions on the electron beam power for avoiding large-scale heating effects are briefly discussed. © 1979 Plenum Publishing Corporation.