Resistance anomaly and linear magnetoresistance in thin flakes of itinerant ferromagnet Fe<sub>3</sub>GeTe<sub>2</sub>
Honglei Feng, Yong Li, Youguo Shi, Hong-Yi Xie, Yongqing Li, Yang Xu
Abstract
Research interests in recent years have expanded into quantum materials that display novel magnetism incorporating strong correlations, topological effects, and dimensional crossovers. Fe 3 GeTe 2 represents such a two-dimensional van der Waals platform exhibiting itinerant ferromagnetism with many intriguing properties. Up to date, most electronic transport studies on Fe 3 GeTe 2 have been limited to its anomalous Hall responses while the longitudinal counterpart (such as magnetoresistance) remains largely unexplored. Here, we report a few unusual transport behaviors on thin flakes of Fe 3 GeTe 2 . Upon cooling to the base temperature, the sample develops a resistivity upturn that shows a crossover from a marginally –ln T to a – T 1/2 dependence, followed by a lower-temperature deviation. Moreover, we observe a negative and non-saturating linear magnetoresistance when the magnetization is parallel or antiparallel to the external magnetic field. The slope of the linear magnetoresistance also shows a nonmonotonic temperature dependence. We deduce an anomalous contribution to the magnetoresistance at low temperatures with a scaling function proportional – HT 1/2 , as well as a temperature-independent linear term. Possible mechanisms that could account for our observations are discussed.