The limitation mechanism of J_c-θ characteristics in YBa₂Cu₃O_7-x thin film with a single low angle grain boundary

The angular dependencies of critical current density (J_bc) in a YBa₂Cu₃O_7-x film on a bicrystal SrTiO₃ substrate were measured. At low magnetic field, J_bc was limited by the low angle grain boundary (LAGB), regardless of the angle, θ between the c-axis and magnetic field. However, the limitation mechanism of J_bc-θ curves changed at kink positions in high magnetic field. The vortex pinning in the grains determined J_bc for low θ, but J_bc at high θ was still limited by the LAGB. The crossover of J_bc limitation mechanism is discussed to understand the angular dependence of critical current in coated conductors.