Large Magnetoresistance and Reconfigurable Spin Filtering Efficiency Induced by Nonvolatile Electrical Control of Magnetism in van der Waals Sc2CO2/Bilayer-NiCl2/Sc2CO2 Multiferroic Heterostructures

Abstract

The large magnetoresistance (MR) effect produced by nonvolatile electrical control of magnetism in van der Waals (vdW) multiferroic heterostructures with strong magnetoelectric coupling effect holds great significance for designing high-efficiency and low-dissipation spintronic devices beyond Moore’s law. Here, we propose a vdW multiferroic heterostructure composed of a bilayer-NiCl₂ clamped by two ferroelectric monolayer-Sc₂CO₂ (Sc₂CO₂/bilayer-NiCl₂/Sc₂CO₂ vdW heterostructure) and investigate the electronic structure, magnetoelectric coupling properties, and the in-plane spin-dependent transport of the proposed vdW multiferroic heterostructure using first-principles calculations. It is found that the interlayer magnetic coupling of the sandwiched bilayer-NiCl₂ can be reversibly switched between antiferromagnetic (AFM) and ferromagnetic couplings by electrically reversing the ferroelectric polarization direction of the top and bottom Sc₂CO₂ layers, respectively. By nonvolatile electrical control of the interlayer magnetic coupling of the sandwiched bilayer-NiCl₂, a large MR effect of about 470–500%, and the maximum spin filtering efficiency of about 70% can be produced in the Sc₂CO₂/bilayer-NiCl₂/Sc₂CO₂ vdW heterostructure under zero bias, and the spin filtering efficiency can be effectively tuned by applying an electric field. Intriguingly, the built-in effective electric field along the out-of-plane direction between the two Sc₂CO₂ layers yields a spin filtering efficiency of up to 63–65% under zero bias, even in the interlayer AFM state. Our work presents a promising avenue for developing high-efficiency and low-dissipation spintronic devices.