A variable temperature Kerr microscope in a 3D vector superconducting magnet

Magneto-optic Kerr effect (MOKE) with micrometer-scale spatial resolution opens up an avenue to study the magnetic structures in layered materials. In this talk, we report a variable temperature Kerr microscope housed in a room temperature bore superconducting magnet with the vector magnetic field up to 2 T in any direction. Because the sample and magnet are cooled separately by closed cycle cryocoolers, the sample temperature and magnetic field could be controlled independently. Thus, the sample temperature could be varied continuously from 10 K to 300 K or more. By employing the photoelastic modulation technique, the Kerr angle resolution is better than 0.5 mRad at a tunable wavelength. While the spatial resolution is smaller than 3 um by using an aspherical lens, the scan area could reach to 120 x 120 um² with the aid of a 2D Galvo-Mirrors. To demonstrate its powerful performance, we will show experimental results in mechanically exfoliated few-layer magnetic materials such as chromium trihalides.