Perforated tips for high-resolution in-plane magnetic force microscopy

Abstract

We describe a technique to modify batch-fabricated magnetic force microscopy (MFM) tips to allow high resolution imaging of the in-plane components of stray field. A hole with a diameter as small as 20 nm was milled through the magnetic layer at the apex of each tip using a focused ion beam. The tips were magnetized in the direction parallel to the sample plane. The hole at the apex forms a small pole gap, and the MFM signal arises from interaction of the stray field leakage from this gap with magnetic charge distribution of the sample. Data tracks written in recording media have been used to characterize tip performance.

Switching Magnetization Magnetic Force Microscopy — An Alternative to Conventional Lift-Mode MFM

“…Koblishka et al [21] and S. Huang et al [22] milled standard MFM tips and prepared high-aspect-ratio tips using focused ion beam (FIB). L. Folks et al [23] applied the FIB milling to increase the MFM lateral resolution and magnetic sensitivity. Recently, F. Wolny [24] fabricated MFM tip by filling CNT with ferromagnetic iron.…”

Focused Ion Beam Milled CoPt Magnetic Force Microscopy Tips for High Resolution Domain Images

“…Focused ion beam (FIB) milling has been used previously to realize this MFM-tip modification. Folks et al [4] made a hole as small as 20 nm at the apex of a CoCr tip to improve the resolution of in-plane components of the stray field and to identify a 50-nm transition. Liu et al [5] sharpened the tip using an FIB and then coated a 30-nm exchanged coupled antiferromagnet-ferromagnet multilayer on the tip.…”

Nanometer scale patterning using focused ion beam milling

“…It is used in the development of nanoelectronics, 1 nanoscale probe recording, 2 and magnetoelectronics, 3 or for high resolution modification of MFM tips. 4 We have recently demonstrated the ability of the FIB technique to fabricate 50 nm wide Hall effect sensors. 5 The main advantage of FIB is that it is a very rapid, dry technique, as compared to electron beam lithography for instance.…”