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Gigantic Current Control of Coercive Field and Intrinsic Spin-Orbit-Torque in Topological van-der-Waals Ferromagnetic Metal Fe3GeTe2
Seoul National University1
Controlling magnetic states by a small current is essential for the next-generation of energy-efficient spintronic devices. The emerging spin-orbit-torque-Magnetic-Random-Access-Memory (SOT-MRAM) is the most promising commercial magnetic-RAM in the near future. Unfortunately, the switching current density and power dissipation are still too high for conventional magnet/heavy-metal based SOT-MRAM, prompting the development of new large-SOT systems. On the other hand, very recently, van-der-Waals (vdW) magnetic materials have rapidly emerged as key members of the field of two-dimensional materials and device physics [2-7]. Among all the magnetic vdW materials, Fe3GeTe2 received special attention because it is the only topological ferromagnetic vdW metal.
Here we report that surprisingly an in-plane current can tune the magnetic state of nm-thin vdW ferromagnet Fe3GeTe2 from a hard magnetic state to a soft magnetic state, through substantial reduction of the coercive field. This surprising finding is possible because the in-plane current produces a highly unusual type of gigantic spin-orbit torque for Fe3GeTe2, which is directly related to the large Berry curvature and so its band topology. And we further demonstrate a working model of a new nonvolatile magnetic memory based on the principle of our discovery in Fe3GeTe2, controlled by a tiny current. Our findings open up a new window of exciting opportunities for magnetic vdW materials with potentially huge impacts on the future development of spintronic.
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