A Novel Model for Magnetic Field‐Modulated Spin‐Filtering Effects and Magnetic Memory Devices

ABSTRACT Exploring high‐density, low‐energy data storage is critical for future information technology. Room‐temperature magnetic tunnel junctions (MTJs) have enhanced storage density, yet conventional MTJs with semiconductor or metal barriers struggle to achieve 100% spin‐polarized current. We propose a 2D ferromagnetic half‐metal MTJ model that leverages coercivity differences to modulate interlayer spin configuration, improving spin filtering without charge carriers or pinning layers. Using first‐principles calculations, we investigate the properties and provide a detailed theoretical analysis of the 2D FeBr 2 /FeI 2 FM‐HM‐MTJ. An external magnetic field controls interlayer spin alignment via coercivity differences, enabling selective carrier filtering and yielding ∼100% spin polarization at zero bias, corresponding to a TMR ratio of ∼1739.67%. Notably, the FeBr 2 /FeI 2 MTJ generates two distinct magnetic signals in the parallel (P) and antiparallel (AP) magnetization states. By flipping the interlayer magnetic configuration, digital information can be encoded as “1” and “0”, thus facilitating information storage. According to Monte Carlo simulations, the device operates within a temperature range of 0∼190 K. This model is extendable to MTJs composed of other half‐metallic materials. Our work presents an efficient magnetic field modulation method for 2D ferromagnetic vdW heterostructures, enabling selective spin current filtering and magnetic storage devices.