Compact design, construction, and evaluation of an in situ ±90° rotatable magnetic force microscope in a 12 T superconducting magnet.

Cryogenic magnetic force microscopy (MFM) is a powerful technique capable of resolving exotic magnetic textures with nanoscale resolution in real-space. We introduce a cryogenic rotatable MFM (CRMFM) that enables the visualization of in situ evolution of magnetic domains by rotating magnetic samples between -90° and +90° within a 12 T superconducting magnet. By continuously rotating the sample under an external magnetic field, the direction of the magnetic field can be varied from out-of-plane to in-plane, enabling microscopic analysis experiments that require vector magnetic fields within the CRMFM system. By using CRMFM measurements, we successfully transformed long magnetic stripe domains into isolated magnetic bubble domains and proposed a novel strategy for visualizing stripe-bubble transitions in magnetic domains. Additionally, we demonstrated that the CRMFM system can generate high-quality MFM images under in-plane magnetic fields up to 12 T. Our research provides a framework for visualizing the interaction between ferromagnetism and magnetic field direction, facilitating the study of magnetic crystal anisotropy.