Spatial resolution and switching field of magnetic force microscope tips prepared by coating Fe/Co-Pt layers

Magnetic force microscope tips are prepared by coating Si tips of 4 nm radius with magnetic bi-layer film consisting of soft magnetic material of Fe(x nm) and hard magnetic material Co-Pt alloy (20–x nm), 0 ≤ x ≤ 20. The effects of layer thickness ratio and stacking sequence on the spatial resolution and the switching field are investigated. Higher resolutions are observed for tips prepared by coating Co-Pt alloy followed by Fe film deposition compared with those prepared by employing the opposite deposition sequence. The resolution improves from 11.0 to 8.2 nm whereas the switching field decreases from 1525 to 475 Oe with increasing the x value from 0 to 20 nm. The present study has shown a possibility of tuning MFM tip performance by employing a soft/hard dual layer structure.