Two-dimensional vortex dynamics in a ratchet washboard planar pinning potential in the presence of thermal fluctuations is considered on the basis of a Fokker-Planck equation. Explicit expressions for two nonlinear anisotropic voltages (longitudinal and transverse with respect to the current direction) are derived and analyzed. The physical origin of these odd (with respect to magnetic field or transport current direction reversal) voltages is caused by the interplay between the even effect of vortex guiding and the ratchet asymmetry. Both voltages are going to zero in the linear regimes of the vortex motion [i.e., in the thermally activated flux flow (TAFF) and Ohmic flux flow (FF) regimes] and have a bumplike current or temperature dependence in the vicinity of the highly nonlinear resistive transition from the TAFF to the FF.

• Received 21 July 2009

DOI:https://doi.org/10.1103/PhysRevB.80.214526