Motivated by the recent observations of the peak effect in high-Tc YBCO superconductors, we re-examine the origin of this unusual phenomenon. We propose that the sharp peak in the critical current as a function of temperature or magnetic field is an interesting manifestation of vortex-lattice melting in the presence of weak random pinning. Specifically, the rise of the critical current with increasing temperature or field is a result of a crossover from the Larkin pinning length to a length scale set by thermal fluctuations.
ASJC Scopus subject areas
- Physics and Astronomy(all)