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

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