Utilisation of beam-blanking in electron beam-induced voltage contrast studies of high-Tc superconducting thin films

Beam-blanking has been used to study the influence of electron beam pulse length and pulse current on voltage generation in a superconducting YBa₂Cu₃O_7-x (YBCO) thin film microbridge. Pulse lengths from a few μS up to 400 μS have been studied. A peak in recorded voltage was found to occur for pulse lengths of 80 to 100 μS. This provides an upper limit for useful pulse lengths of approximately 100 μS. Further work is required to ascertain whether this is sample dependent and particularly whether it is dependent on sample thickness. Measured voltage across the microbridge was found to increase parabolically with beam current at temperatures well below the transition temperature (Tc). At temperatures close to Tc a less rapid rise in voltage as a function of beam current was observed. This is ascribed to the beam power, and subsequent heating, being sufficient to drive locally the superconductor normal and trace out the local resistivity curve.