Field-Free Manipulation of Two-Dimensional Ferromagnet CrTe 2 by Spin-Orbit Torques.

Electrical manipulation of magnetic states in two-dimensional ferromagnetic systems is crucial in information storage and low-dimensional spintronics. Spin-orbit torque presents a rapid and energy-efficient method for electrical control of the magnetization. In this letter, we demonstrate a wafer-scale spin-orbit torque switching of two-dimensional ferromagnetic states. Using molecular beam epitaxy, we fabricate two-dimensional heterostructures composed of low crystal-symmetry WTe 2 and ferromagnet CrTe 2 with perpendicular anisotropy. By utilizing out-of-plane spins generated from WTe 2 , we achieve field-free switching of the CrTe 2 perpendicular magnetization. The threshold switching current density in CrTe 2 /WTe 2 is 1.2 × 10 6 A/cm 2 , 20 times smaller than that of the CrTe 2 /Pt control sample even with an external magnetic field. In addition, the switching behavior can be modulated by external magnetic fields and crystal symmetry. Our findings demonstrate a controllable and all-electric manipulation of perpendicular magnetization in a two-dimensional ferromagnet, representing a significant advancement toward the practical implementation of low-dimensional spintronic devices.