We report numerical simulations of magnetic flux patterns in asymmetric 45° -tilt grain boundaries in YBa2Cu3O7-x superconducting films. The grain boundaries are treated as Josephson junctions with a critical current density jc(x) alternating rapidly along the junctions with a typical length scale which is much less than Josephson penetration depth. We demonstrate the existence of Josephson vortices with fractional flux quanta for both periodic and random jc(x). A method is proposed to extract these "fractional" vortices from experimental flux patterns.
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - 1 Oct 2001