Dimpling in critical current density vs. magnetic field angle in YBa2Cu3O7 films irradiated with 3-MeV gold ions

Magnetic-field-angle θ dependence of critical current density Jc was measured in YBa2Cu3O7 films irradiated with 3-MeV gold ions. Such films were recently found to show large pinning force arising from point-like irradiation defects. A dimpled line-shape of Jc(θ) and its variation with magnetic field strength were revealed that could be well described by a simple model based on flux-lattice shear and Blatter scaling. Our results strongly suggest that vortex elasticity and electron-mass anisotropy coordinately produce the characteristic Jc anisotropy, called “shoulders,” in cuprate and iron-pnictide films.