Optimization of the HF-MFM technique

To optimize the performance of the high-frequency magnetic force microscopy (HFMFM) technique, we investigate the effect of varying the frequency of the amplitude modulation on the magnetic contrast achieved. As samples, we employ hard disk writer poles. We find that the optimum condition for the HF-MFM operation is the use of a modulation frequency being about half of the cantilever resonant frequency. Together with optimized cantilevers, a clear improvement of the magnetic imaging is obtained. Furthermore, we can deduce that the optimum parameters for imaging must be determined for each experimental system (hard disk writer pole and cantilever) individually.