Gigantic Current Control of Coercive Field and Magnetic Memory Based on Nanometer-Thin Ferromagnetic van der Waals Fe3 GeTe2

Adv Mater. 2021 Jan;33(4):e2004110. doi: 10.1002/adma.202004110. Epub 2020 Dec 6.

Abstract

Controlling magnetic states by a small current is essential for the next-generation of energy-efficient spintronic devices. However, it invariably requires considerable energy to change a magnetic ground state of intrinsically quantum nature governed by fundamental Hamiltonian, once stabilized below a phase-transition temperature. Here, it is reported that, surprisingly, an in-plane current can tune the magnetic state of the nanometer-thin van der Waals ferromagnet Fe3 GeTe2 from a hard magnetic state to a soft magnetic state. It is a direct demonstration of the current-induced 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 Fe3 GeTe2 . In addition, a working model of a new nonvolatile magnetic memory based on the principle of the discovery in Fe3 GeTe2 , controlled by a tiny current, is further demonstrated. The findings open up a new window of exciting opportunities for magnetic van der Waals materials with potentially huge impact on the future development of spintronic and magnetic memory.

Keywords: 2D topological ferromagnetic metal Fe3GeTe2; current-tunable coercive field; magnetic van der Waals materials; spintronic and magnetic memory; unusually large spin-orbit torque.