非均匀交换各向异性铁磁介质的非线性表面自旋波

利用Landau-Lifshitz 方程，研究了具有非均匀交换各向异性的半无限大铁磁体的非线性表 面自旋波理论。导出了部分钉扎纯交换铁磁介质的磁化强度所满足的边界条件和非线性表面 自旋波的色散关系，并获得了自旋波振幅沿z方向驻波的一维非线性Schrdinger方程和包 络振幅沿平面传播的二维非线性Schrdinger方程，结果表明铁磁体磁化强度的包络振幅随时空变化的性质是由二维非线性Schrdinger方程决定的。因此预言铁磁介质的表面非线性激发应是二维孤波的形式。对于弱非线性表面自旋波，对非线性Schrdinger方程存在孤子形式解的可能性作了讨论. 关键词： 表面自旋波 Landau-Lifshitz方程 非线性Schrdinger方程 孤子

Nonlinear surface spin waves on ferromagnetic media with inhomogeneous exchange anisotropy

The theory of nonlinear surface spin waves in pure-exchange semi-infinite ferrom agnetic media with inhomogeneous exchange anisotropy has been considered by usin g the Landau-Lifshitz equation. For partly pinned pure-exchange ferromagnet, the boun-dary condition for magnatization of this system is derived, and the nonlinear dispersion relation for these waves is obtained. The one-dimensional(stationary wave along the z-direction) and two-dimensional(2D)(travelling wave in the oxy plane) nonlinear Schrdinger equations which are satisfied by the spin -wave envelope amplitude of the magnetization, are derived. It is shown that the amplitude of the magnetization is determined by the 2D nonlinear Schrdinger e quation. From this, we predict that the nonlinear excitation on the surface of m agnetic materials should be of 2D soliton form. For weakly nonlinear spin waves, the possibi-lity of soliton formation on the basis of 2D nonlinear Schrdi nger equation has been discussed in detail.