Hard magnetic properties in nanoflake van der Waals Fe₃GeTe₂

Two-dimensional van der Waals materials have demonstrated fascinating optical and electrical characteristics. However, reports on magnetic properties and spintronic applications of van der Waals materials are scarce by comparison. Here, we report anomalous Hall effect measurements on single crystalline metallic Fe₃GeTe₂ nanoflakes with different thicknesses. These nanoflakes exhibit a single hard magnetic phase with a near square-shaped magnetic loop, large coercivity (up to 550 mT at 2 K), a Curie temperature near 200 K and strong perpendicular magnetic anisotropy. Using criticality analysis, the coupling length between van der Waals atomic layers in Fe₃GeTe₂ is estimated to be ~5 van der Waals layers. Furthermore, the hard magnetic behaviour of Fe₃GeTe₂ can be well described by a proposed model. The magnetic properties of Fe₃GeTe₂ highlight its potential for integration into van der Waals magnetic heterostructures, paving the way for spintronic research and applications based on these devices.