Theoretical Description of the High-Frequency Magnetic Force Microscopy Technique

We present a theoretical description of the high-frequency magnetic force microscopy (HF-MFM) technique. There are currently two operation modes: 1) the measurement of high-frequency currents via their magnetic stray fields and 2) the measurement of stray fields emanating from hard disk writer poles. The advanced HF-MFM technique employs the amplitude-modulation technique in order to convert the HF signal to the frequency range of the cantilever. Using the point-dipole approximation, we calculate the resulting force onto the cantilever for both cases.