Room-Temperature and Tunable Tunneling Magnetoresistance in Fe₃GaTe₂-Based 2D van der Waals Heterojunctions

Abstract

Magnetic tunnel junctions (MTJs) based on van der Waals (vdW) heterostructures with sharp and clean interfaces on the atomic scale are essential for the application of next-generation spintronics. However, the lack of room-temperature intrinsic ferromagnetic crystals with perpendicular magnetic anisotropy has greatly hindered the development of vertical MTJs. The discovery of room-temperature intrinsic ferromagnetic two-dimensional (2D) crystal Fe 3 GaTe 2 has solved the problem and greatly facilitated the realization of practical spintronic devices. Here, we demonstrate a room-temperature MTJ based on a Fe 3 GaTe 2 /WS 2 /Fe 3 GaTe 2 heterostructure for the first time. The tunneling magnetoresistance (TMR) ratio is up to 213% with a high spin polarization of 72% at 10 K, the highest ever reported in Fe 3 GaTe 2 -based MTJs up to now. A tunneling spin-valve signal robustly persists at room temperature (300 K) with a bias current down to 10 nA. Moreover, the spin polarization can be modulated by bias current and the TMR shows a sign reversal at a large bias current. Our work sheds light on the potential application of low-energy consumption in all-2D vdW spintronics and offers alternative routes for the electronic control of spintronic devices.

Tunable long-range spin transport in a van der Waals Fe3GeTe2/WSe2/Fe3GeTe2 spin valve

“…However, the realization of tunneling of different spin states through separate conducting channels is significantly suppressed by spin flipping or scattering mechanisms at the interface. 9 In this view, a 2D vdW heterostructure with uniform barrier thickness can greatly reduce these scattering phenomena, leading to the enhanced tunneling of charge carriers and spin transport. 10,11 Notably, the possibility of ferromagnetic ordering due to spontaneous magnetization in 2D vdW crystals is hindered by thermal fluctuations at finite temperatures.…”

Electronic Noise Spectroscopy of Quasi-Two-Dimensional Antiferromagnetic Semiconductors

“…Research interest in low-dimensional magnetic systems has been rapidly increasing since the experimental discovery of various forms of magnetism in the few- and single-layer limits of quasi-two-dimensional (quasi-2D) materials. − These developments have enabled designs of novel spintronic devices with applications in sensing, data storage, and information processing. , In the realm of magnetic materials used in spintronics, there has been a considerable focus on ferro- and ferrimagnetic (FM) compounds that were either electrically insulating or electrically conductive, while much less attention has been devoted to antiferromagnetic semiconductors (AFMS). Notably, the effect of spin ordering on the dynamics of charge carrier transport and electronic noise in AFMS, especially across the material’s magnetic transition, is often overlooked.…”

Self-Modulated Magnetism in Two-Dimensional Ferromagnet Fe3GeTe2 Induced by Ambient Effects

“…Some studies highlight room-temperature ferromagnetism of 2D semiconducting magnets − or non-van der Waals ferromagnet, − and they show weak ferromagnetism and soft magnetic properties. Through element substitution in FGT, robust room-temperature ferromagnetism and PMA have been realized in Fe 3 GaTe 2 , making it more attractive to fabricate novel 2D-vdW-integrated spintronic devices. , Furthermore, interlayer coupling of FGT can be effectively modulated due to weak vdW force between interlayers by strain, proximity effect, and light–matter interactions . As an ideal platform to understand 2D magnetism, FGT has shown some fascinating physical phenomena such as the topological Hall effect, magnetic skyrmions, − and quantum criticality .…”