Three-dimensional simulation of the disturbance of magnetic domain walls by magnetic force microscope tips

The micromagnetics of the interaction of a strong 3D magnetic force microscope tip with a 180° asymmetric Bloch domain wall in an 80 nm {100} iron film has been simulated numerically using cubic elements on a 3D lattice. The distortion of the wall is found to be quite well localized on the scale of the tip dimensions, 60×60 nm2. The force of attraction between tip and film and the changes in self-energy of the wall and in the energy of the tip-sample system have been calculated for various positions of the tip. The strong attraction between tip and sample is slightly reduced (∼5%) when the tip is directly over the central vortex in the wall.