Atomic-scale modeling of nanoconstrictions

Using a Heisenberg model along with Monte Carlo, it is demonstrated that localized domain walls can be formed inside nanoconstrictions. The origin of the localized domain wall lies in the competition between atomic-scale exchange and the shape anisotropy. This leads to high sensitivity of the domain wall width on the shape of the nanoconstriction. Moreover, it is shown that ferromagnetic ordering is considerably reduced in these localized domain walls.