The formation of elliptical Néel-type skyrmions via anisotropic exchange and Dzyaloshinskii–Moriya interactions

Abstract

We demonstrate control over elliptical Néel skyrmion morphology and stability in 2D chiral magnets through synergistic engineering of anisotropic interactions: exchange anisotropy (ηJ) and Dzyaloshinskii–Moriya anisotropy (ηD) to systematically manipulate skyrmion ellipticity, density, and size via Monte Carlo simulations and theoretical analysis. Phase diagrams reveal distinct magnetic states, including metastable skyrmion lattices (|Q|>60), differentiated by topological charge Q, where strong anisotropy (|ηJ|>0.8 or |ηD|>0.8) transforms skyrmions into helical states with exchange interactions exhibiting superior strain tunability over Dzyaloshinskii–Moriya interaction. Under magnetic fields (Bz>8 T), skyrmions compress to minimal elliptical configurations prior to annihilation, exhibiting non-monotonic aspect-ratio (La/Lb) scaling governed by ellipticity parameter f=(La−Lb)/(La+Lb). This work establishes an anisotropy-parameter framework for designing strain-programmable racetrack memory and nonvolatile storage elements in low-symmetry magnetic materials.