Volume 37 (2013) Issue 3-2 Pages 107-110
Magnetic force microscope (MFM) tips are prepared by coating Si tips of 5, 4, and 3 nm radiuses with Co films by varying the thickness in a range between 5 and 80 nm. The effects of base-Si tip radius and coating thickness on the MFM spatial resolution are investigated. With increasing the thickness from 5 to 20 nm, the resolutions of MFM tips prepared by using Si tips of 5, 4, and 3 nm radiuses improve from 10.2 to 7.7 nm, from 12.1 to 7.3 nm, and from 12.1 to 6.6 nm, respectively. This is due to an increase of signal detection sensitivity related with the coating thickness. With further increasing the thickness, the resolution declines due to an increase of tip radius. The resolution is affected by both the detection sensitivity and the tip radius. A higher resolution is obtained by using a sharper base-Si tip. Magnetic bits of a perpendicular medium recorded at 1900 kFCI (bit length: 13.4 nm) are distinguishable in the MFM image observed by using a tip prepared by coating Si tip of 3 nm radius with 20-nm-thick Co film. An MFM tip prepared by coating sharp base-tip with Co film of optimized thickness is useful to investigate the magnetization structure of future recording media.