Foldover, Quasi-Periodicity, and Spin-Wave Instabilities in Ultra-Thin Magnetic Films

• Published in: IEEE transactions on magnetics Vol. 42; no. 10; pp. 3195 - 3197
• Main Authors: d'Aquino, M., Bertotti, G., Serpico, C., Mayergoyz, I.D., Bonin, R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-10-2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Cross-disciplinary physics: materials science; rheology; Dynamic tests; Dynamical systems; Dynamics; Equations; Exact sciences and technology; Ferromagnetic resonance; foldover; Instability; Landau-Lifshitz-Gilbert (LLG) equation; Magnetic analysis; Magnetic anisotropy; Magnetic films; Magnetic resonance; Magnetism; Magnetostatics; Materials science; Microwaves; Other topics in materials science; Perpendicular magnetic anisotropy; Perturbation methods; Physics; Saturation magnetization; spin-waves; Stability; Steady state; Thin films; Ferromagnetic resonance; Proceedings; spin-waves; Landau-Lifshitz-Gilbert (LLG) equation; foldover; Magnetic materials; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2006.880154

We study magnetization dynamics in a uniaxial ultra-thin ferromagnetic disk subject to spatially uniform microwave external fields. As a consequence of the rotational invariance of the system, the only admissible spatially uniform steady states are periodic (P-modes) and quasi-periodic (Q-modes) modes. The stability of P-modes versus spatially uniform and nonuniform perturbations is studied by using spin-wave analysis and the instability diagram for all possible P-modes is computed. The predictions of the spin-wave analysis are compared with micromagnetic simulations