The high frequency response of the soft magnetic pole tip in the thin film inductive head is crucial for the noise analysis of computer hard disk. A micromagnetic model is established in a mesoscopic soft magnetic thin film to analyze the domain pattern as well as the initial permeability in a wide frequency range from 10MHz to 18GHz. The simulated domain patterns in the pole tip, a vortex- and ladder-type, are chosen as the initial conditions for the high-frequency response studies. The scaling law of the permeability is analyzed at different amplitudes of the alternating external magnetic field. It is found that in the ladder-type domains the high frequency response is much better than that in the vortex-type domains, which agrees with experiment. A simplified explanation of the simulation result is discussed based on the analysis of the nonlinear Landau–Liftshitz equation.
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