DIRECT OBSERVATION OF MAGNETIC VORTICES IN SUPERCONDUCTORS USING ELECTRON WAVES

The development of a coherent field-emission electron beam has made it possible to observe microscopic magnetic lines of force by detecting the electron-wave phase shifts that are due to vector potentials. Elec tron-holographic interference microscopy has been used to observe magn etic lines of force of magnetic vortices in superconductors, and Loren tz microscopy has been used to observe the dynamics of the vortices. T he observation of vortices not only helps us understand the microscopi c mechanism of flux pinning, which holds the key to practical applicat ions of superconductors, but also clarifies fundamental phenomena of s uperconductivity which have implications for the more general physical phenomena.