Fabrication of Tips for Magnetic Force Microscopy Employing Magnetic Multilayer Structures

Magnetic force microscope (MFM) tips are prepared by coating Si tips of 4 nm radius with [Co(1 nm)/M(1 nm)](20) (M = Pt, Pd, Ni) multilayer films. An MFM tip prepared by coating 40- nm- thick Co film is employed as a reference tip. The influences of M layer material on the spatial resolution and the switching field of MFM tip are investigated. The spatial resolutions of Co/M multilayer coated tips are estimated to be within 9.4 +/- 0.3 nm for all the M materials, which is about 6% inferior to that of Co coated tip (8.8 nm). Higher switching fields of 1425 and 825 Oe are respectively observed for the tips coated with Co/Pt and Co/Pd multilayers, whereas the field of tip coated with Co/Ni multilayer is 275 Oe which is similar to that of Co coated tip (325 Oe). The switching field is influenced by the magnetic anisotropy of multilayer film. An MFM tip coated with Co/Pt multilayer film is useful to observe the magnetic domain structure of permanent magnets and magnetic recording media.