Anisotropy of critical current in layered oxide superconductors

Employing the layer structures of the superconducting copper oxides as intrinsic flux pinning centers, we calculate the critical current density as a function of the direction of an external magnetic field. The critical current Jc has a maximum when the magnetic field is parallel to the CuO2 layer. When the magnetic field is tilted from this layer, Jc drastically decreases. The predicted anisotropy of Jc is in good agreement with that observed by experiments.