Fig. 1: Creation of a half vortex ring via a local dipole field.
From: Vortex confinement through an unquantized magnetic flux
a, b Fluxoid quantization of thick and thin slabs. The thick slab accommodates the magnetic flux quantum (Φ0). The thin slab experiences field penetration, but no vortex exists. c, d Creation of a half vortex ring by a local dipole field of an MFM tip in thick slabs and thin slabs. Unquantized magnetic flux can be trapped in the thin slab geometry.
