Atomic-Scale Anisotropy Competition Drives Spin Reorientation in Intercalated 2D Ferromagnets

Abstract

Precise control over magnetic anisotropy (MA) in two-dimensional (2D) van der Waals ferromagnets is essential for advancing next-generation spintronics; however, the atomic-scale mechanisms dictating intercalation-induced MA modulation remain largely unresolved. In this study, we elucidate the microscopic origins of the complex magnetic phase diagram in Cr-intercalated CrTe₂ by integrating layer-resolved density functional theory-based spin–orbit torque (DFT-SOT) calculations with micromagnetic simulations. We uncover a concealed source of perpendicular magnetic anisotropy (PMA) localized within the intercalation layer, which directly competes with the robust surface-driven in-plane magnetic anisotropy (IMA). Macroscopically, this atomic-scale competition drives a thickness-dependent spin reorientation transition, wherein the volumetric accumulation of bulk-like PMA ultimately dominates over interfacial effects. Our findings propose a plausible microscopic framework for understanding the stoichiometry-dependent anisotropy in chromium chalcogenides, offering a promising theoretical perspective for exploring magnetic phases in 2D spintronic architectures.