Scanning Electron Microscope Study of Superconducting Transport in a YBa sub 2 Cu sub 3 O sub (7-delta) Thin Film

By combining electron probing with current biasing at low temperatures a map of the transport characteristics of a mixed phase thin film superconductor can be obtained. The electron beam of a scanning electron microscope (SEM) acts as a local heat source. Under the proper conditions of temperature, bias current, and beam current, variations in the superconducting state can be mapped and compared to microstructure and chemical phase information. This method has recently been applied to high T sub c superconductors to map critical currents and to identify weak links in superconducting paths. We discuss here the possible application of the technique to identify the superconducting phase within a matrix of non-superconducting material.