Current direction dependence of vortex pinning in (103)/(013) oriented YBCO films

The electrical and the superconducting properties of (103)/(013) oriented YBCO films were investigated as a function of the angle of incidence of the current with respect to the in-plane orientation of the film lattice. Unidirectional twin boundary defects are expected to occur in the film, resulting in the observed anisotropy ~/of the resistivity in normal state. Also the current-voltage (V-I) characteristics are affected by the current direction. In this case CuO layer intrinsic pinning is argued to be the origin of the observed behavior.