Interface-Enhanced Ferromagnetism with Long-Distance Effect in van der Waals Semiconductor

Ferromagnetic semiconductors discovered in 2D materials open an avenue for highly integrated and multifunctional spintronics. The Curie temperature (T-C) of existing 2D ferromagnetic semiconductors is extremely low and the modulation effect of their magnetism is limited compared with their 2D metallic counterparts. The interfacial effect is found to effectively manipulate the 3D magnetism, providing a unique opportunity for tailoring the 2D magnetism. Here, it is demonstrated that the T-C of a 2D ferromagnetic semiconductor Cr2Ge2Te6 (CGT) can be enhanced by 130% (from approximate to 65 K to above 150 K) when adjacent to a tungsten layer. The interfacial W-Te bonding contributes to the T-C enhancement with a strong perpendicular magnetic anisotropy, guaranteeing efficient magnetization switching by the spin-orbit torque with a low current density at 150 K. Distinct from the rapid attenuation in conventional magnets, the interfacial effect exhibits a weak dependence on CGT thickness and a long-distance effect (more than 10 nm) due to the weak interlayer coupling inherent to 2D magnets. This work not only reveals a unique interfacial behavior in 2D materials, but also advances the process toward practical 2D spintronics.