Evolution of domain structure in Fe3GeTe2 * *Project supported by the National Key R&D Program of China (Grant Nos. 2017YFA0206202 and 2019YFA0308000), the National Natural Science Foundation of China (Grant Nos. 51871130, 62022089, and 11874405), and the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2019007).

Abstract

Two-dimensional (2D) magnets provide an ideal platform to explore new physical phenomena in fundamental magnetism and to realize the miniaturization of magnetic devices. The study on its domain structure evolution with thickness is of great significance for better understanding the 2D magnetism. Here, we investigate the magnetization reversal and domain structure evolution in 2D ferromagnet Fe3GeTe2 (FGT) with a thickness range of 11.2–112 nm. Three types of domain structures and their corresponding hysteresis loops can be obtained. The magnetic domain varies from a circular domain via a dendritic domain to a labyrinthian domain with increasing FGT thickness, which is accompanied by a transition from squared to slanted hysteresis loops with reduced coercive fields. These features can be ascribed to the total energy changes from exchange interaction-dominated to dipolar interaction-dominated with increasing FGT thickness. Our finding not only enriches the fundamental magnetism, but also paves a way towards spintronics based on 2D magnet.