Observation of vortices in the high-temperature superconductor

We have observed vortices of the high-temperature superconductor using the Bitter technique. Hopping movement of vortices of Y-123 and Bi-2212 single crystal was observed in the temperature range of 50-90 K (T-c) by the therm al energy. We estimated pinning potential by migration length, The pinning potential, we have also observed the vortex pattern of Y-123 QMG sample inc luding Y-211 phase. We found that vortex existed in the grain boundary of Y -211 and Y-123 phase. (C) 2001 Elsevier Science B.V. All rights reserved.