Temperature and thickness dependent magnetization reversal in 2D layered ferromagnetic material Fe3GeTe2

Abstract Advance in the field of two-dimensional (2D) Van der Waals layered magnetic materials have made the atomic-thickness spintronic devices possible in the near future. The application of the 2D layered magnetic materials inevitably involves the magnetization reversal. Here we study the magnetization reversal of the 2D layered material Fe3GeTe2 by means of magnetic and anomalous Hall resistance measurements. We find the reversal process of Fe3GeTe2 flake is temperature and thickness dependent. For thin flakes and at low temperatures, the hysteresis loops have perfect rectangular shapes with large coercivity, indicating the single domain characteristic during the reversal process. With increasing temperature, a cross-over from single domain to multi-domain structure occurs. For bulk and very thick flakes Fe3GeTe2, the nearly zero magnetic remanence and small coercivity demonstrates that the reversal process is accomplished through the formation of multi-domain structure and its gradual evolution with the magnetic field. The change of magnetization reversal with temperature and flake thickness is explained based on the competition between the long-range magnetic dipolar interaction and the perpendicular magnetic anisotropy. The results obtained in this work provide important reference for designing Fe3GeTe2-based spintronic devices.