Propagating two-dimensional magnetic droplets
- 作者：M.A. Hoefer ; mahoefer@ncsu.edu ; M. Sommacal msommac@ncsu.edu
- 关键词：Landau&ndash ; Lifshitz equation ; Ferromagnetic materials ; Spin waves ; Magnetic droplet ; Dynamics of domain structures ; Solitary waves
- 刊名：Physica D
- 出版年：2012
- 期刊代码：55_01672789
- 类别：ph
- 出版时间：1 May, 2012
- 卷：241
- 期：9
- 页码：890-901
- 文件大小：1463 K
摘要
Propagating, solitary magnetic wave solutions of the Landau-Lifshitz equation with uniaxial, easy-axis anisotropy in thin (two-dimensional) magnetic films are investigated. These localized, nontopological wave structures, parametrized by their precessional frequency and propagation speed, extend the stationary, coherently precessing 鈥渕agnon droplet鈥?to the moving frame, a non-trivial generalization due to the lack of Galilean invariance. Propagating droplets move on a spin wave background with a nonlinear droplet dispersion relation that yields a limited range of allowable droplet speeds and frequencies. An iterative numerical technique is used to compute the propagating droplet鈥檚 structure and properties. The results agree with previous asymptotic calculations in the weakly nonlinear regime. Furthermore, an analytical criterion for the droplet鈥檚 orbital stability is confirmed. Time-dependent numerical simulations further verify the propagating droplet鈥檚 robustness to perturbation when its frequency and speed lie within the allowable range.