Construction of a $^3$He Magnetic Force Microscope with a Vector Magnet

We have built a $^3$He magnetic force microscope (MFM) with a base temperature of 300 mK, operating in a vector magnet with the field of Z=9 T, X=2 T, Y=2 T for each axis. We employed a fiber interferometer system for detection of a cantilever motion that includes two auttocube types of walkers for alignment between the fiber end and a cantilever tip. We apply our novel microscope to investigate unconventional magnetic materials and superconductors such as centrosymmetric skyrmion crystals and Heavy Fermion Superconductors. We will show some preliminary MFM images in these systems