Compact piezo-driven rotatable magnetic force microscope in a cryogen-free magnet.

Achieving in situ rotation of scanning probe microscopes (SPMs) within high-field magnets presents significant technical challenges while remaining essential for micron-scale magnetic anisotropy studies. Here, we demonstrate a compact piezoelectrically driven rotatable magnetic force microscope operable within a standard 50 mm bore cryogen-free superconducting magnet, achieving fields up to 12 T and temperatures down to 2 K. The microscope features a nested coaxial piezoelectric scanning tube (PST) design sharing a common base. In this design, the outer PST provides rigid support for the tip holder, while the inner PST actuates the sample approach. This design effectively attenuates common-mode vibration interference (e.g., from the cryocooler) while expanding the scan range by a factor of 1.74 compared to a single PST structure via reverse-direction scanning, maintaining positioning capability for micron-scale devices. Field-controlled magnetic domain evolution imaging in the 2D van der Waals magnet Fe3GaTe2 across multiple angles confirms system functionality. The results reveal strong out-of-plane anisotropy, manifested by magnetization rotation from out-of-plane to in-plane with an angle, and a characteristic 1/cos θ dependence of the saturation field, dominated by domain wall depinning energy. The vibration-resistant rotating microscope structure in cryogen-free magnets can be extended to broader SPM platforms. In addition, the outer PST enables the inertial drive of the tip holder for millimeter-scale searches.