Nonlinearity in spin dynamics of frustrated Kagomé lattice system under harmonic perturbation

Abstract

We investigate the nonlinear spin dynamics of a frustrated Kagomé lattice subjected to a time-periodic magnetic field, focusing on the effects of Dzyaloshinskii–Moriya interaction (DMI), magnetic anisotropy and exchange coupling. Using numerical simulations of the Landau–Lifshitz–Gilbert equation, we analyze the evolution of spin oscillations via Poincaré surface sections and power spectral density across a wide parameter range. At low DMI, weak anisotropy, and small external field strengths, the system exhibits quasi-periodic oscillations governed primarily by exchange interactions. Increasing the DMI strength induces strong aperiodic behavior, with a clear transition to chaotic dynamics, particularly under moderate anisotropy. While strong easy-axis anisotropy tends to stabilize periodic orbits, sufficiently strong DMI can still drive the system into chaos. Furthermore, we show that external fields destabilize oscillations in weakly anisotropic regimes but have limited impact in the presence of strong anisotropy. We also compute the magnon dispersion relation and magnetic resonance (MR) spectra, revealing multi-peak structures at high DMI which indicate the presence of strong nonlinear spin-wave interactions. Our results highlight the critical role of DMI and anisotropy in shaping dynamical responses in Kagomé magnets, affecting the development of spintronic and magnonic devices.