Functionalized Akiyama tips for magnetic force microscopy measurements

In this work we have used focused electron beam induced deposition of cobalt to functionalize atomic force microscopy Akiyama tips for application in magnetic force microscopy. The grown tips have a content of  ≈$90\%$ Co after exposure to ambient air. The magnetic tips were characterized using energy dispersive x-ray spectroscopy and scanning electron microscopy. In order to investigate the magnetic properties, current loops were prepared by electron beam lithography. Measurements at room temperature as well as $4.2K$ were carried out and the coercive field of  ≈$6.8$ mT of the Co tip was estimated by applying several external fields in the opposite direction of the tip magnetization. Magnetic Akiyama tips open new possibilities for wide-range temperature magnetic force microscopy measurements. (paper)