Giant Exfoliation Induced Magnetic Coercivity in Fe3GaTe2

My Contribution

As co-first author on the theory side, I performed GPU-accelerated micromagnetic simulations (MUMAX3) to elucidate the origin of the giant exfoliation-induced magnetic coercivity in Fe₃GaTe₂. I derived the intrinsic magnetocrystalline anisotropy constant Ku1 ≈ 1.73 MJ/m³ by fitting the experimental hard-axis saturation fields to the Stoner-Wohlfarth model, and reproduced both the experimental saturation fields and the characteristic anomalous hysteresis loops observed in transport measurements.

My simulations demonstrated that exfoliated flakes behave as coherent, single-domain Stoner-Wohlfarth macrospins governed by high intrinsic magnetocrystalline anisotropy, explaining the crossover from domain-mediated reversal in bulk crystals to quasi-coherent rotation in thin flakes. I further resolved Brown’s Paradox by introducing a localized defect with reduced anisotropy, showing that the macroscopic switching field is governed by the weakest spot (nucleation-driven reversal) rather than the bulk anisotropy. These results ruled out alternative models — including surface anisotropy, grain-boundary pinning, and skyrmionic textures — confirming that the enhanced coercivity arises from the system approaching the single-domain limit upon exfoliation.