Antisymmetric magnetoresistance in van der Waals Fe ₃ GeTe ₂ /graphite/Fe ₃ GeTe ₂ trilayer heterostructures

Abstract

With no requirements for lattice matching, van der Waals (vdW) ferromagnetic materials are rapidly establishing themselves as effective building blocks for next-generation spintronic devices. We report a hitherto rarely seen antisymmetric magnetoresistance (MR) effect in vdW heterostructured Fe3GeTe2 (FGT)/graphite/FGT devices. Unlike conventional giant MR (GMR), which is characterized by two resistance states, the MR in these vdW heterostructures features distinct high-, intermediate-, and low-resistance states. This unique characteristic is suggestive of underlying physical mechanisms that differ from those observed before. After theoretical calculations, the three-resistance behavior was attributed to a spin momentum locking induced spin-polarized current at the graphite/FGT interface. Our work reveals that ferromagnetic heterostructures assembled from vdW materials can exhibit substantially different properties to those exhibited by similar heterostructures grown in vacuum. Hence, it highlights the potential for new physics and new spintronic applications to be discovered using vdW heterostructures.

Gigantic Current Control of Coercive Field and Magnetic Memory Based on Nanometer‐Thin Ferromagnetic van der Waals Fe3GeTe2

“…Besides, exciting new behavior was also found in the FGT-based heterostructure, such as the unconventional 3-state magnetoresistance. [15] Electrical modulation of the magnetic anisotropy or coercivity is critical to realizing energy-efficient spintronic devices such as memory. For information storage, the magnetic anisotropy should be high enough to minimize the information loss by fluctuations.…”

From two- to multi-state vertical spin valves without spacer layer based on Fe3GeTe2 van der Waals homo-junctions

“…In this context, two-dimensional (2D) van der Waals (vdW) layered materials [15,16]-especially emerging 2D magnetic materials [17][18][19][20][21]-have provided researchers with another versatile way to tackle such obstacles in traditional magnetic multilayer systems [22]. In particular, homo-or hetero-junctions incorporating these vdW materials without direct chemical bonding, avoiding the associated intermixing effect and defect-induced gap states, may show performance exceeding that of covalently bonded magnetic multilayers [23][24][25][26][27][28].…”

Robust ferromagnetism in wafer-scale monolayer and multilayer Fe3GeTe2

“…This makes FGT all the more desirable for MRAM 32 . Closely related application prospects are found in magnetic tunnel junction heterostructures of FGT/graphite/FGT, which display promising characteristics of 160% tunneling magnetoresistance at low temperature 33 .…”

“…npj 2D Materials and Applications (2020)33 Published in partnership with FCT NOVA with the support of E-MRS 1234567890():,;…”