Vortex motion through the splayed configurations of columnar defects

We report large current enhancements inY Ba 2 Cu 3 O 7-σ with splayed columnar defects. An optimalrelative splay angle is Θ opt = 10° for the planar splay distribution. The vortex motion through gaussian splay appears to be controlled by the large-angle tails of the distribution. The regimes are observed where vortex motion isenhanced rather thansuppressed by splay.