A new theoretical probe for the magnetic force microscope

The magnetic force microscope (MFM) is established as a valuable tool for t he analysis of magnetic structures. The standard design of MFM incorporates a silicon tip coated with a magnetic material. However, these tips are sub ject to several inherent problems, e.g. changing characteristics over time due to damage or magnetic hysteresis. A new theoretical electromagnetic MFM probe is introduced here. Although electromagnetic MFM has been discussed before by Zhou et al. (J. Vac. Sci. Technol. A 17 (1999) 2233), the design presented here is a different approach. Two different probe iterations and their magnetic field intensity distribution are modelled. The probe imaging capability is compared using the reciprocity principle (Wright and Hill, A ppl. Phys. Lett. 68 (1996) 1726) to image the simulated force interaction b etween a sample and the probe fields. Thus, images of a sample's magnetic d istribution are produced by the convolution of the different probe gradient field distributions and the sample magnetisation. Both perpendicular and l ongitudinal magnetisation patterns were simulated with the different probe iterations. This clearly showed the improvement of the second probe iterati on, particularly for longitudinal patterns. The practical use of the new pr obe is also discussed, and future work outlined. (C) 2001 Published by Else vier Science B.V.