Journal of Electron Microscopy 51:S3-S11 (2002)
© 2002 Oxford University Press
Full-length paper |
Lorentz microscopy of vortices in superconductors
Present address: Advanced Research Laboratory, Hitachi, Ltd, Hatoyama, Saitama 350-0395, Japan SORST, Japan Science and Technology Corporation, 3-4-15 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan E-mail: tonomura{at}harl.hitachi.co.jp
A bright field-emission electron beam was used to observe magnetic vortices in superconducting thin films by electron holography and Lorentz microscopy. Especially in Lorentz microscopy, the dynamic behaviour of individual vortices became directly observable for the first time. As material defects can be observed simultaneously, the vortex pinning phenomena, which are indispensable for practical applications of superconductors, can now be observed microscopically and dynamically. This study revealed the existence of various kinds of vortex movements, such as individual hopping among defects, vortex rivers, and vortexantivortex pair annihilation.
Keywords Lorentz microscopy, vortex, superconductor, field-emission electrons, Nb, Bi-2212