Abstract
Magnetic force microscope (MFM) tips are prepared by coating three-sided pyramid base Si tips of 4 nm radius with Co film by employing an ultra-high vacuum evaporation system. The effects of film thickness and coating direction on the MFM spatial resolution are investigated. For a thickness of 10 nm, the one-side coated MFM tip has a lower MFM signal detection sensitivity and a lower resolution compared with those of the two- and the three-side coated tips due to that the volume of film coated around the top part of base tip is smaller in the case of one-side coating. With increasing the thickness from 10 to 20 nm, the detection sensitivity increases and the resolution improves regardless the coating direction. As the coating thickness further increases, the resolution deteriorates due to the increases in radius and surface roughness of tip. The MFM tips prepared by coating one-, two-, and three-sides of base tips with 20-nm-thick films show resolutions of 7.7 ± 0.2, 7.3 ± 0.2, and 6.9 ± 0.2 nm, respectively. Higher resolutions are observed in the order of one- < two- < three-side coated tip. The top parts of one-and two-side coated tips are slightly bent toward the film coating directions. The tip bending is interpreted to decrease the resolution. The resolution is influenced by both tip shape and detection sensitivity.
