Recent progress and challenges in magnetic tunnel junctions with 2D materials for spintronic applications

Abstract

As Moore's law is gradually losing its effectiveness, developing alternative high-speed and low-energy-consuming information technology with post-silicon advanced materials is urgently needed. The successful application of tunneling magnetoresistance (TMR) in magnetic tunnel junctions (MTJs) has given rise to a tremendous economic impact on magnetic informatics, including MRAM, radio-frequency sensors, microwave generators and neuromorphic computing networks. The emergence of twodimensional (2D) materials brings opportunities for MTJs based on 2D materials which have many attractive characters and advantages. Especially, the recently discovered intrinsic 2D ferromagnetic materials with high spin-polarization hold the promise for next-generation nanoscale MTJs. With the development of advanced 2D materials, many efforts on MTJs with 2D materials have been made both theoretically and experimentally. Various 2D materials, such as semi-metallic graphene, insulating h-BN, semiconducting MoS2, magnetic semiconducting CrI3, magnetic metallic Fe3GeTe2 and some other recently emerged 2D materials are discussed as the electrodes and/or central scattering materials of MTJs in this review. We discuss the fundamental and main issues facing MTJs, and review the current progress made with 2D MTJs, briefly comment on work with some specific 2D materials, and highlight how they address the current challenges in MTJs, and finally offer an outlook and perspective of 2D MTJs.

Inkjet printing of two-dimensional van der Waals materials: a new route towards emerging electronic device applications

“…As a result of continued efforts to find and synthesize magnetic vdW materials, studies on magnetism-related research including spintronics of 2D magnetic vdW materials have been initiated. 9,49,56,58,76,78,79 In addition, the 2D heterostructure platform has a strong advantage without the lattice mismatch concern, while fabricating magnetic heterostructures by using conventional magnetic materials and device fabrication is difficult due to lattice distortion, which can also distort the magnetic dipole alignment. Similarly, research on 2D topological insulators and Weyl semimetals has begun, as they have recently discovered.…”

Giant tunnelling electroresistance through 2D sliding ferroelectric materials

“…7 Ferroelectric tunnel junctions, composed of two metal electrodes separated by a thin ferroelectric barrier, can achieve different tunnelling electroresistance (TER) through polarization switching. [17][18][19][20] The application of the vdW sliding ferroelectric BBN as the ultrathin barrier can build the 2D sliding ferroelectric tunnel junctions (SFTJs). Ferroelectric BBN has clean, uniform and weak interfacial coupling in its vdW structures as well as polarization switching by an applied voltage.…”

Electronic structure, magnetoresistance and spin filtering in graphene|2 monolayer-CrI33|graphene van der Waals magnetic tunnel junctions

“…, defect/disorder in the electrodes and barrier, interface diffusion and poor thermal stability that lead to low tunnel magnetoresistance (TMR). 1,2 Unlike conventional multilayer MTJ devices where two ferromagnetic layers are separated by a nonmagnetic insulator layer, ferromagnetic vdW-monolayers can serve simultaneously as the tunneling barrier and TMR-related free ferromagnetic layer in vdW-MTJs. 7–10 This functional combination enables spintronic devices to be ultracompact and to be modulated efficiently by electrical means.…”