Room temperature gate-tuned magnetic phase transition in a van der Wals magnet

Cheng Tan

Cheng Tan, RMIT

Finding tunable van der Waals (vdW) ferromagnets that operate at above room temperature is an important research focus in physics and materials science. Most vdW magnets are only intrinsically magnetic far below room temperature and magnetism with square-shaped hysteresis at room temperature has yet to be observed.

Here, we report magnetism in a quasi-2D magnet Cr1.2Te2 observed at room temperature (290 K). This magnetism was tuned via a protonic gate with an electron doping concentration up to 3.8 × 10 21 cm-3.

We observed non-monotonic evolutions in both coercivity and anomalous Hall resistivity. Under increased electron doping, the coercivities and anomalous Hall effects (AHEs) vanished, indicating a doping-induced magnetic phase transition. This occurred up to room temperature. DFT calculations showed the formation of an antiferromagnetic (AFM) phase caused by the intercalation of protons which induced significant electron doping in the Cr1.2Te2. The tunability of the magnetic properties and phase in room temperature magnetic vdW Cr1.2Te2 is a significant step towards practical spintronic devices.

About the presenter

Cheng Tan is currently working as a postdoctoral researcher working on a FLEET industry project He recently finished his PhD, working with Prof Lan Wang (RMIT) to study Van der Waals (vdW) magnetic materials and heterostructures for their potential in quantum anomalous Hall effect (QAHE) devices within FLEET’s Research theme 1 and Enabling technology B. In such devices, electron transport can occur without scattering and without an applied magnetic field or ultra-low temperature, making them ideal candidates for future low-energy electronics.