Dataset for "Epitaxial Co2MnSi with intrinsic magnetocrystalline anisotropy as a route to bias-field-free nonlinear half-metal magnonics at the nanoscale"

This is the data set associated with the preprint arXiv.2606.03431. --- Abstract: Half-metallic Heusler compounds like Co2MnSi allow to bridge magnonic and spintronic functionality for hybrid unconventional computing approaches with sought-after properties like 100% spin polarization and associated low Gilbert damping $\alpha\leq 10^{-3}$. However, the desirable material parameters are inherently tied to the crystal lattice with a particularly critical dependence on structural order in Co2MnSi. To date, the successful fabrication of nanoscale devices with robust structural integrity remains yet a challenge, and consequently the impact of the material parameters on the resulting nonlinear spin-wave dynamics remains largely unexplored. Here, we report on a study of linear and nonlinear spin-wave dynamics in transversally magnetized Co2MnSi waveguides with impeccable crystalline ordering. We show that epitaxial, L21-ordered Co2MnSi exhibits an intrinsic cubic anisotropy with first- and second-order contributions, stabilizing a magnetization alignment along the crystal $\langle110\rangle$ directions. We confirm the implication of an unaffected crystal structure resulting in preserved magnetic properties in the patterned structures. Herein, the persistent magnetocrystalline anisotropy reshapes the spin-wave dispersion which yields a first-order nonlinear instability suppression range extending over several GHz - even for vanishing bias fields. Moreover, the intrinsic magnetocrystalline anisotropy can be exploited to counteract shape demagnetization for a stabilized low bias field operation in the favourable Damon-Eshbach geometry with high group velocities and decay lengths. Together with the proven half-metallicity and ultralow Gilbert damping, this research establishes Co2MnSi as a robust, scalable platform towards bias-field-free nonlinear half-metal magnonics.