Vortex Pinning due to Strong Quasiparticle Scattering at Antiphase Boundaries inYBa2Cu3O7−δ

Abstract

Using a recently developed quantitative magneto-optical method we investigated the vortex pinning mechanism in ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ films. Parallel oriented planar antiphase boundaries (APB's), generated in epitaxial thin films grown on vicinal ${\mathrm{SrTiO}}_{3}$ (001), serve as well defined pinning sites, yielding extraordinary high pinning forces and an anisotropic critical current density ${j}_{c}$ up to $\ensuremath{\approx}30%$ of the depairing current. The measured angular and temperature dependence as well as the magnitude of ${j}_{c}$ prove that pinning at APB's is dominated by quasiparticle scattering induced variation of condensation energy, characteristic of superconductors with anisotropic order parameter.