ACTIVATED FLUX CREEP IN LAYERED HIGH-TEMPERATURE SUPERCONDUCTORS

We study thermally activated flux creep in layered superconductors in the case when the magnetic field is parallel to the layers and vortices move across the layers. We assume that the sample is without imperfections, so that the pinning is due to an interaction between vortices and the layered microstructure of the superconductors. The height of the energy barrier that vortices overcome during each activation process is calculated in the case when the vortex lattice period is commensurate with the interlayer spacing. This energy barrier depends on the transport current: it grows at small currents and goes to zero linearly when j→jcwhere jcis the depinning current. © 1990 Plenum Publishing Corporation.