Observation of quantized vortices in superconductors by electron waves

Coherent field-emission electron beams and electron holography techniques have made it possible to produce interference micrographs from which the phase distribution of the wave function of an electron beam transmitted through an object relative to that of a reference beam can be measured to within 1100th of the electron wavelength. This has opened up a new way to make ultrafine measurements of material structures and of electromagnetic field distributions. Magnetic lines of force of quantized vortices in a superconducting thin film, for example, have been directly observed by electron-holographic interference microscopy. In addition, the dynamics of individual vortices interacting with pinning centers has been observed in real time by Lorentz microscopy.