Temperature and layer dependent magneto-optical Kerr properties in (nearly room temperature) van der Waals metallic ferromagnet Fe4GeTe2 enabled by large-area Au-assisted mechanical exfoliation

In recent years, the exploration of two-dimensional van der Waals materials has revealed significant potential for novel magnetic and electronic applications. Among these, metallic ferromagnets such as Fe₄GeTe₂, which exhibit nearly room temperature ferromagnetism, are of particular interest due to their unique magnetic and electronic properties[4]. However, the integration of such materials into practical devices has been hindered by challenges related to sample preparation and scalability. Here, we report on the temperature and layer-dependent magneto-optical Kerr properties of Fe₄GeTe₂, new method enabled by large-area Au-assisted mechanical exfoliation[1][2]. Using this new method allows for control over layer thickness and uniformity, providing a robust platform for studying the material's magneto-optical response as well as providing a new way of exfoliation on other air stable crystals [1]. Our findings demonstrate clear ferromagnetic behavior that persists across a range of temperatures, approaching near room-temperature stability. The temperature and thickness-dependent Kerr measurements reveal insights into the magnetic anisotropy and interlayer coupling of Fe₄GeTe₂, suggesting its potential for integration into spintronic devices [3].