Improved Durable Vortex Core MFM Tip

Vortex-Core magnetic force microscopy (VC MFM) promises magnetic tip durability and long-term calibration of its magnetic moment that is crucial for quantitative scanning. It uses the vortex core of a ferromagnetic disk located at the tip apex as a magnetic probe. However, our experience showed that MFM images might be distorted when scanning magnetic objects larger than 100 nm due to a VC shift generated by the stray field of the scanned sample. We addressed the problem by changing the tip geometry and introducing artificial VC pinning at the disk center. These steps are essential for improving the VC tip for quantitative scanning. The scanning experiments with the optimized VC tip showed improved characteristics of the magnetic images - spatial resolution of the tip was on the level of commercial MFM tip with certain details depicted even better.