  The interplay between vortex guiding and the Hall effect in superconducting
Nb films with periodically arranged nanogrooves is studied via four-probe
measurements in standard and Hall configurations and accompanying theoretical
modeling. The nanogrooves are milled by focused ion beam and induce a symmetric
pinning potential of the washboard type. The resistivity tensor of the films is
determined in the limit of small current densities at temperatures close to the
critical temperature for the fundamental matching configuration of the vortex
lattice with respect to the pinning nanolandscape. The angle between the
current direction with respect to the grooves is set at seven fixed values
between $0^\circ$ and $90^\circ$. A sign change is observed in the temperature
dependence of the Hall resistivity $\rho_\perp^-$ of as-grown films in a narrow
temperature range near $T_c$. By contrast, for all nanopatterned films
$\rho_\perp^-$ is nonzero in a broader temperature range below $T_c$, allowing
us to discriminate between two contributions in $\rho_\perp^-$, namely one
contribution originating from the guided vortex motion and the other one caused
by the Hall anomaly just as in as-grown Nb films. All four measured resistivity
components are successfully fitted to analytical expressions derived within the
framework of a stochastic model of competing isotropic and anisotropic pinning.
This provides evidence of the model validity for the description of the
resistive response of superconductor thin films with washboard pinning
nanolandscapes.
