Green’s function for magnetostatic surface waves and its application to the study of diffraction patterns
Green’s function for magnetostatic surface waves and its application to the study of diffraction patterns
复制标题
静磁表面波格林函数及其在衍射图样研究中的应用
DOI：
10.1103/physrevb.84.064437
复制
发表时间：
2011
影响因子：
3.7
通讯作者：
D. Ricketts
中科院分区：
文献类型：
--
作者：
S. Tamaru;J. Bain;M. Kryder;D. Ricketts
本文给出了静磁表面波在真实的空间和频域中的二维绿色函数（GF），在切向磁化板几何形状，包括有限阻尼的影响，由点波源发射的MSSW的空间传播模式。该理论首先在静磁近似下导出自旋系统的非齐次微分方程。通过引入Hermitian算子将该方程转化为Sturm-Liouville问题，并通过本征函数展开技术求解，该技术以二维傅里叶逆变换的形式产生GF的积分表达式。所得到的GF演示各种功能特性的MSSW，如强各向异性传播，从波源的能量流的角度限制，其极限角被定义为临界角的群速度，和半奥斯汀光束沿着。然后，我们计算的一维空间分布和二维衍射图案的MSSW传播卷积的GF与各种波源分布，并将它们与实验结果进行比较观察切向磁化坡莫合金薄膜。这些数值和实验结果之间的比较表明，良好的协议。
This paper presents the two-dimensional (2D) Green’s function (GF) of magnetostatic surface waves (MSSWs) in real space and the frequency domain, i.e., the spatial propagation pattern of MSSWs emitted by a point wave source in a tangentially magnetized slab geometry, including the effect of finite damping. The theory first derives an inhomogeneous differential equation of the spin system under a magnetostatic approximation. This equation is translated into a Sturm-Liouville problem by introducing a Hermitian operator, and solved by the eigenfunction expansion technique, which yields an integral expression of the GF in the form of a 2D inverse Fourier transform. The obtained GF demonstrates various features characteristic of MSSWs, such as strongly anisotropic propagation, angular confinement of energy flow from the wave source whose limit angle is defined as the critical angle for the group velocity, and semicaustic beams along. We then calculate the 1D spatial profiles and 2D diffraction patterns of MSSW propagation by convolving the GF with various wave source distributions, and compare them with experimental results observed on a tangentially magnetized Permalloy film. Comparison between these numerical and experimental results shows excellent agreement.