Focused ion beam deposition of Co$_{71}$Cr$_{17}$Pt$_{12}$ and Ni$_{80}$Fe$_{20}$ on tips for magnetic force microscopy*

We demonstrate that a focused ion beam can deposit magnetic coatings on cantilevers used for atomic force microscopy, thereby producing a sensor for magnetic force microscopy. This technique is highly versatile, allowing the convenient deposition of complex or expensive materials, such as Co$_{71}$Cr$_{17}$Pt$_{12}$. A second material chosen for this demonstration was permalloy (Ni$_{80}$Fe$_{20})$. We show magnetic images acquired with these cantilevers to illustrate their excellent properties and the differences between coatings. In principle, multilayer coatings could be easily made with this technique.