Highly efficient nonvolatile magnetization switching and multi-level states by current in single van der Waals topological ferromagnet Fe3GeTe2

Fe3GeTe2는 자성 반데르발스 물질 가운데 거의 유일한 금속 성질을 보이고 있다. 특히 이 물질은 Fe d 밴드에 의한 자기 위상학적인 성질을 보이며, 높은 강자성 상전이 온도를 가지고 있다. 이런 자기 위상학적인 성질로 인한 비정상 홀 효과(AHE)를 보이며, 우리는 이미 AHE이 전류에 의한 특이한 스핀-오비 토크에 의해서 제어된다는 것을 보였다. 이번 연구에서는 Fe3GeTe2를 이용하여 단일 물질로 이루어진 자기 소자를 제작하는데 성공하였다. 이렇게 구현된 자기 소자는 전류를 통해 멀티 비트를 갖는 자성 메모리로 쓰일 수 있다는 획기적인 성질을 가지고 있다.  

Abstract: Robust multi-level spin memory with the ability to write information electrically is a long-sought capability in spintronics, with great promise for applications. Here, nonvolatile and highly energy-efficient magnetization switching is achieved in a single-material device formed of van-der-Waals (vdW) topological ferromagnet Fe₃GeTe₂, whose magnetic information can be readily controlled by a tiny current. Furthermore, the switching current density and power dissipation are about 400 and 4000 times smaller than those of the existing spin-orbit-torque magnetic random access memory based on conventional magnet/heavy-metal systems. Most importantly, multi-level states, switched by electrical current are also demonstrated, which can dramatically enhance the information capacity density and reduce computing costs. Thus, the observations combine both high energy efficiency and large information capacity density in one device, showcasing the potential applications of the emerging field of vdW magnets in the field of spin memory and spintronics.

참여 연구원: Kaixuan Zhang, 이유진, Matt Coak, 김정현, 손수한, 황인호, 김도헌, 박제근

Advanced Functional Materials 온라인 게재 

https://onlinelibrary.wiley.com/doi/10.1002/adfm.202105992