Angular dependence of stress-induced spin-wave dynamics in antivortices stabilized in square FeGa nanodots

We investigate the angular dependence of stress-induced spin-wave dynamics in magnetic antivortices stabilized in square FeGa nanodots by means of micromagnetic simulations. The application of in-plane uniaxial stress generates an effective magnetoelastic anisotropy whose magnitude and orientation are systematically varied to analyze their impact on the stability, core position, and dynamic response of the antivortex state. A magnetic state diagram reveals well-defined regions where the antivortex remains stable, as well as angular and stress thresholds beyond which the configuration becomes unstable and relaxes into a different magnetic state. Within the stable regime, the antivortex core undergoes pronounced angular-dependent displacements, reflecting the strong sensitivity of the antivortex topology to the orientation of the applied stress. Ferromagnetic resonance analysis shows that the spin-wave spectrum exhibits a multibranch structure composed of discrete modes whose frequencies, intensities, and angular dispersion are strongly modulated by the stress orientation. At higher stress amplitudes, the spectra display enhanced angular modulation, mode hybridization, and the emergence of instability-induced spectral fragmentation. Spatial mode analysis reveals a rich variety of excitations ranging from core-localized modes to extended standing-wave patterns governed by the combined effects of square confinement and angular magnetoelastic anisotropy. These results demonstrate that angular stress tuning provides an efficient and energy-efficient route to control antivortex stability and spin-wave dynamics, opening new perspectives for reconfigurable magnonic devices based on topological magnetic textures.