Micromagnetic Analysis of Effective Magnetic Dipole Position in Magnetic Force Microscope Tip

An accurate micromagnetic model of the magnetic force microscope (MFM) tip has been developed to calculate the effective dipole and its position in a simple point probe model, which are important in the quantitative explanation of MFM images. The pyramid-shaped MFM tips are considered in this paper; so cuboid cells in the body, as well as triangular prism and quadrangle pyramid cells at the edge are included to accurately describe the geometrical shape of the tip. The effective position of the magnetic point dipole and the MFM tip field distribution are analyzed, based on the calculated domain structures in the tips with different materials parameters. The simulated tip fields are compared carefully with that of the point probe model usually utilized in the MFM tips.