Vortex matter in mesoscopic superconductors
Zusammenfassung der Projektergebnisse
In this project, we have significantly advanced experimental techniques for spatially-resolved observation of the nucleation and motion of vortices in mesoscopic superconductors. By performing systematic measurements with the low-temperature laser scanning microscope we have directly observed of guidance of vortices by artificial micro-holes ('antidots') in superconducting thin films. The motion traces of vortices from antidot to antidot have been successfully visualized. We also developed a novel technique for direct measurements of the local critical current, which can be used as a quantitative method for the analysis of vortex motion in micro-patterned thin films. Furthermore, we have made further progress in imaging dissipative processes at microwave frequencies. We demonstrated a new spatial partition method for the high-frequency photo-response correlated with inductive and resistive changes in microwave impedance. The results show that the dominant sources of microwave nonlinearities are strongly localized in the resistive domains and are associated with the vortex entry and their microwave-driven motion. Besides that, we have observed a precursor of the crossover from the motion of Abrikosov vortices to kinematic vortices in phase-slip lines. We found that, under certain conditions, phase-slip lines coexist with the flux flow of vortices. A detailed study of the competition between these two alternative dissipation mechanisms in superconductors remains a challenging goal for the future.
Projektbezogene Publikationen (Auswahl)
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A. Lukashenko, A. V. Ustinov, A. P. Zhuravel, E. Hollmann, and R. Wördenweber, Laser scanning microscopy of guided vortex flow in microstructured high-Tc films, J. Appl. Phys. 100, 023913 (2006).
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A. P. Zhuravel, A. G. Sivakov, O. G. Turutanov, A. N. Ömelyanchouk, S. M. Anlage, A. Lukashenko. A. V. Ustinov, and D. Abraimov, Laser scanning microscopy of HTS films and devices (review article), Fiz. Nizk. Temp. 32, 775-794 (2006).
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A. P. Zhuravel, S. M. Anlage, and A. V. Ustinov, Measurement of local reactive and resistive photoresponse of a superconducting microwave device, Appl. Phys. Lett. 88, 212503 (2006).
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A. P. Zhuravel, S. M. Anlage, and A. V. Ustinov, Microwave current imaging in passive HTS components by low-temperature laser scanning microscopy. J. Supercond. and Nov. Magn. 19, 625 (2006).
