Geometry and anisotropy-induced magnetic states and spin-wave dynamics in lens-shaped Permalloy nanostructures

Sifuentes-Rivera J.; Saavedra E.; Sarmiento C.V.; Guimarães A.P.; Vigo-Cotrina H. · Physica B: Condensed Matter (2026) · DOI: 10.1016/j.physb.2026.419314

Resumen

We investigate how geometric confinement and perpendicular magnetic anisotropy jointly govern the lowest-energy magnetic configurations and spin-wave dynamics of lens-shaped Permalloy nanostructures by means of micromagnetic simulations. Magnetic phase diagrams reveal a sequence of equilibrium states, including vortex, vortex-like, skyrmionium, skyrmion, and quasi-uniform configurations, whose stability is determined by the interplay between aspect ratio (δ) and perpendicular magnetic anisotropy (Kz). Increasing the aspect ratio progressively suppresses topologically nontrivial magnetic textures, leading to a transition toward in-plane and perpendicular quasi-uniform states. The dynamic response of the equilibrium configurations was characterized through dynamic susceptibility spectra and spatial distributions of the resonant spin-wave modes. Distinct frequency evolutions and mode profiles were identified for each magnetic state, demonstrating that modifications of the magnetic ground state are directly reflected in the spin-wave response. These results show that geometry and perpendicular magnetic anisotropy provide complementary control parameters for engineering both equilibrium magnetic states and spin-wave excitations in lens-shaped nanostructures, highlighting their potential for future magnonic and spintronic applications.

Instituciones: Universidad Nacional Jorge Basadre Grohmann; Universidad Privada del Norte