Scanning aperture photoemission microscopy for magnetic imaging

Magnetic imaging has been demonstrated by photoemission microscopy in which spatial resolution is achieved by scanning an aperture across the sample. To achieve magnetic contrast, the difference between photoemission current with right and left circularly polarized light is recorded while holding the aperture-surface distance to 30 nm. We used conical gold tips with apertures as small as 30 nm, drilled by a focused ion beam. Images of Co/Pt multilayer films show a magnetic contrast of ±2% and a resolution (25%-75% of a step) of 30 nm. Resolution better than 10 nm should be achievable with smaller apertures. With this imaging method, there is no magnetic interaction between sample and tip, and ultrafast time resolution should be achievable. © 2000 American Institute of Physics.