Domain Wall in Ferromagnetic nanoconstrictions
     180° domain walls in ferromagnetic nanoconstrictions are investigated by classical atomic Monte Carlo simulations. The wall width is determined by the effective length of the constriction (as little as 1nm). The wall can have a Néel-like configuration for constrictions much narrower than the normal wall width, but there is a crossover region with vortex-type walls before reaching a Bloch-type wall at larger diameters. In very narrow constrictions, effects of the atomic-scale structure become evident as the domain-wall structure depends on the number of atoms in the cross section. The simulations indicate the possibility of spontaneous thermal fluctuations between different magnetic modes in walls smaller than about 10 nm. (link)