Flux creep and flow in YBa2Cu3O7 epitaxial films: role of planar defects

The resistive state behavior for YBa₂Cu₃O ₇ epitaxial films deposited by laser ablation onto SrTiO₃(100) single crystals has been studied. The I-V curves and R(H,T) have been measured. The dissipation processes and temperature and field dependencies of the elementary pinning force and pinning potential are shown to be adequately described by the spatially inhomogeneous superconducting order parameter model and the existence of easy flux slip channels. Such channels seem to be formed along planar defects and can be disclosed experimentally, depending on the direction of the acting force, along or across the defect plane. It is clear that in the second case the planar defects serve as pins and can result in significant enhancement of the vortex activation energy. It is suggested that this factor can be responsible for the difference between vortex activation energy values derived from magnetic moment relaxation experiments and the transport properties of high-temperature superconductors