Manipulating Ferromagnetism in Few‐Layered Cr2Ge2Te6

The discovery of magnetism in 2D materials offers new opportunities for exploring novel quantum states and developing spintronic devices. In this work, using field‐effect transistors with solid ion conductors as the gate dielectric (SIC‐FETs), we have observed a significant enhancement of ferromagnetism associated with magnetic easy‐axis switching in few‐layered Cr2Ge2Te6. The easy axis of the magnetization, inferred from the anisotropic magnetoresistance, can be uniformly tuned from the out‐of‐plane direction to an in‐plane direction by electric field in the few‐layered Cr2Ge2Te6. Additionally, the Curie temperature, obtained from both the Hall resistance and magnetoresistance measurements, increases from 65 to 180 K in the few‐layered sample by electric gating. Moreover, the surface of the sample is fully exposed in the SIC‐FET device configuration, making further heterostructure‐engineering possible. This work offers an excellent platform for realizing electrically controlled quantum phenomena in a single device. In field‐effect transistors with solid ionic conductors as the gate dielectric, the easy‐axis of the ferromagnetism of Cr2Ge2Te6 thin flakes can be uniformly tuned from the out‐of‐plane direction to the in‐plane direction by an electric field, coinciding with a significant increase of the Curie temperature. The surface of the sample is fully exposed in this type of devices, making further heterostructure‐engineering possible.