Vortex dynamics in thin films ofYBa2Cu3O7−xwith three-dimensional nanoscale patterns

Abstract

We have machined vertical transport structures in YBCO thin films in which the current is constrained to flow along the $c$ axis. When current is forced to flow outside the $a\text{\ensuremath{-}}b$ planes in YBCO a component of the Lorentz force arises acting along them. Consequently we have been able to directly measure the magnitude of the pinning force acting on vortices moving within the $a\text{\ensuremath{-}}b$ planes, and demonstrate vortex cutting, vortex channeling, and pinning by twin boundaries. Such measurements are not otherwise possible in $c$-axis films. We show that vortex channeling can be inhibited by a Lorentz force component acting perpendicularly to the channel. This is ascribed to pinning of the vortices within the channel by the channel wall.