Vortex lattice mobility and effective pinning potentials in the peak effect region in YBCO crystals

G. PASQUINI; V. BEKERIS

Mumbay, India

Workshop; International Vortex Workshop 2005; 2005

Abstract: The Peak Effect (PE) in the critical current density in both lowand high temperature superconductors has been subject of a large amount ofexperimental and theoretical work in the last years. In the case of YBCO,crucial discussions describing a dynamic or a static picture are notsettled. In that region of field and temperature the mobility of the vortexlattice (VL) is found to be dependent on the dynamical history. Recently wereported evidence that the VL reorganizes and accesses to robust VLconfigurations (VLCs) with different effective pinning potential wellsarising in response to different system histories. One of thekeys to understand the nature of the PE is to investigate the VL behavior inthe vicinity of the various VLCs in the region of the PE. The stability of these VLCs was investigated and it was found that they have distinct characteristic relaxation times, which may be related to elastic or plastic creep processes. In this paper we review some of these results and propose a scenario to describe the PE in YBCO crystals