  Domain walls in nano-constrictions are investigated with a focus on thermal
properties. In general, the magnetization component perpendicular to the easy
axis which in a domain wall usually occurs has a value different from the
easy-axis bulk magnetization value with a separate phase transition at a
critical temperature below the Curie temperature. Since this effect is the more
pronounced the smaller the domain wall width is we investigate it especially in
domain walls with a confined geometry, using analytical arguments, mean-field
theory and Monte Carlo simulations. Our findings may contribute to the
understanding of magneto-resistive effects in domain walls with sizes of only a
few atomic layers, as e. g. in nano-contacts or nano-constrictions.
