Field-induced crossover of criticalities of vortex dynamics in thin films
Abteilung Festkörperphysik, Universität Ulm, D-89069
2 National Laboratory for Superconductivity, Institute of Physics and Center for Condensed Matter Physics, P.O. Box 603, Beijing 100080, PRC
3 Department of Electronics, Nankai University, Tianjing 300071, PRC
Accepted: 11 March 1998
By analyzing I-V characteristics (E-j curves), which were experimentally determined on thin films in magnetic fields Be varying from 0 T to 5 T, we find that the transition of the linear resistivity signaling superconductivity exhibits different criticalities for different magnetic fields. Starting with a Berezinskii-Kosterlitz-Thouless transition at for , one induces a crossover to a quasi-2D or 3D vortex-glass transition at a finite Tg for magnetic fields below a few kOe, and finally a "true” 2D vortex-glass with for higher fields. We argue that this field-induced crossover of criticalities is a general feature of all strongly anisotropic high-Tc superconductors.
PACS: 74.60.Ge – Flux pinning, flux creep, and flux-line lattice dynamics / 74.60.Jg – Critical currents / 74.72.Fq – Tl-based cuprates
© EDP Sciences, 1998