Magnetic domain walls in constrained geometries

Magnetic domain walls have been studied in micrometer-sized Fe₂₀Ni₈₀ elements containing geometrical constrictions by spin-polarized scanning electron microscopy and numerical simulations. By controlling the constriction dimensions, the wall width can be tailored and the wall type modified. In particular, the width of a 180^^∘ N\'eel wall can be strongly reduced or increased by the constriction geometry compared with the wall in unconstrained systems.