  We study the features of the superconductivity nucleation and vortex
configurations in superconductors with modulated disorder. Using the
Ginzburg-Landau-type theory with spatially varying diffusion coefficient, we
uncover and explain the switching between the vortex-defect attraction to the
repulsion upon the increase in the external magnetic field. It is shown that
for rather weak applied magnetic fields, a superconducting nucleus localized
near the region with the suppressed diffusion coefficient possesses a nonzero
vorticity whereas the increase in the magnetic field can lead to a transition
into the state with zero winding number. We demonstrate the manifestations of
this switching phenomenon in superconductors with a large number of defects by
performing numerical simulations of the vortex structures in superconductors
with periodic spatial profiles of the diffusion coefficient. The obtained
results clarify the physics of the vortex arrangement in several classes of the
superconducting materials including one-dimensional superlattices and
nanopatterned superconductors with regular arrays of the defects characterized
by the increased concentration of nonmagnetic impurities.
