| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1820188 | Physica C: Superconductivity and its Applications | 2008 | 6 Pages |
Magneto-optical imaging technique is applied to visualize vortex distribution in superconducting networks and in highly anisotropic superconductor Bi2Sr2CaCu2O8+y under tilted magnetic fields. We have succeeded in visualizing the vortex distribution in a finite-size superconducting network with the unit cell size as small as 6 × 6 μm2. We have also visualized the ratchet effect of pancake vortices induced by the time-asymmetric motion of Josephson vortices. The ratchet effect appears most clearly at the similar condition as the vortex lensing effect. The ratchet efficiency diminishes strongly as a function of frequency and it is almost completely suppressed above 1 kHz. Such a strong frequency dependence of the vortex ratchet effect is discussed based on the skin effect controlled by c-axis resistivity.
