Compact dynamic cantilever magnetometry

Dynamic cantilever magnetometry (DCM) is a highly sensitive technique for detecting magnetization in individual low-dimensional magnetic materials, superconductors, and magnetotactic bacteria. However, existing instruments use a three-dimensional positioning stage to focus the laser on the cantilever, resulting in a bulky probe head, ∼100 mm in diameter, which limits their widespread use in small-aperture commercial magnets. Here, we develop a laser autofocus technique using materials with specific thermal expansion coefficients, eliminating the need for the positioning stage. By employing this technique, we develop a compact DCM system with a diameter of ∼22 mm and demonstrate its applications in the Physical Property Measurement System, the Janis 9T magnet, and high field magnets, exemplified by studies on a van der Waals ferromagnet CrGeTe3 and a Kagome metal ZrV6Sn6. The development of this compact DCM system is expected to enable broader adoption of this technique and promote research into advanced low-dimensional materials.