Off-equilibrium properties of vortex creep in superconductors
Department of Mathematics, Imperial College 180 Queen's Gate,
London SW7 2BZ, UK
2 Università di Napoli "Federico II", Dipartimento di Scienze Fisiche INFM and INFN - Via Cintia, 80126 Napoli, Italy
Accepted: 29 March 2001
We study a model for the dynamics of vortices in type-II superconductors. In particular, we discuss glassy "off-equilibrium" properties and "aging"in magnetic creep. At low temperatures a crossover point is found, Tg, where relaxation times seem to diverge à la Vogel-Tamman-Fulcher. Magnetic creep changes by crossing Tg: above Tg power law creep is found asymptotically followed by stretched exponential saturation; below Tg the creep is logarithmic and vortex motion strongly subdiffusive. In this region violation of time translation invariance is found along with important dynamical scaling properties.
PACS: 05.50.+q – Lattice theory and statistics (Ising, Potts, etc.) / 75.10.-b – General theory and models of magnetic ordering / 47.32.Cc – Vortex dynamics
© EDP Sciences, 2001