INTRINSIC CHANNELING OF VORTICES ALONG THE AB PLANE IN VICINAL YBA2CU3O7-DELTA FILMS

We have measured the critical current density j(c) as a function of th e orientation of a magnetic field in vicinal YBa2Cu3O7-delta films. Wh en both field and Lorentz force lie within the ab plane, we observe a minimum in j(c). At high temperatures, as the c-axis coherence length approaches the ab-plane distance, the minimum in j(c) could not be obs erved, indicating that this effect is related to the breakdown of the rectilinear vortex state for fields at a small angle to the ab planes. Our results are the first demonstration of intrinsic channeling of vo rtex strings along the ab planes.