论文标题
通过Bloch结构壁散射自旋波的散射：偶极相互作用的影响
Scattering of spin waves by a Bloch domain wall: effect of the dipolar interaction
论文作者
论文摘要
众所周知，各向异性铁磁体中的Bloch域壁对自旋波是透明的。通过有效的各向异性相互作用近似磁矩之间的偶极相互作用来得出该结果。在本文中，我们研究了域壁的旋转波的散射，并考虑到偶极相互作用的全部复杂性，并在扭曲的波出生的近似中扰动地对其进行处理。由于偶极相互作用的特殊性，这种近似的实现并不简单。 The difficulties are circumvented here by realizing that the contribution of the dipolar interaction to the spin wave operator can be split into two terms: i) an operator that commutes with the spin wave operator in absence of dipolar interaction, and ii) a local operator suitable to be treated as a perturbation in the distorted wave Born approximaton.我们分析了这种方法中获得的散射参数。事实证明，反射系数一般不会消失，即使在正常发病率下，传输波也会遭受横向移位。通过使自旋波穿过一系列分离良好的域壁，这种侧向移动可以增强。由于反射系数在正常的入射率下消失，因此在域壁上的散射不会削弱外向的自旋波。这种效果对于控制宏伟设备中的自旋波可能非常有用。
It is known that a Bloch domain wall in an anisotropic ferromagnet is transparent to spin waves. This result is derived by approximating the dipolar interaction between magnetic moments by an effective anisotropy interaction. In this paper we study the the scattering of spin waves by a domain wall taking into account the full complexity of the dipolar interaction, treating it perturbatively in the distorted wave Born approximation. Due to the peculiarities of the dipolar interaction, the implementation of this approximation is not straightforward. The difficulties are circumvented here by realizing that the contribution of the dipolar interaction to the spin wave operator can be split into two terms: i) an operator that commutes with the spin wave operator in absence of dipolar interaction, and ii) a local operator suitable to be treated as a perturbation in the distorted wave Born approximaton. We analyze the scattering parameters obtained within this approach. It turns out that the reflection coefficient does not vanish in general, and that the transmitted waves suffer a lateral shift even at normal incidence. This lateral shift can be greatlty enhanced by making the spin wave go through an array of well separated domain walls. The outgoing spin wave will no be attenuated by the scattering at the domain walls since the reflection coefficient vanishes at normal incidence. This effect may be very useful to control the spin waves in magnonic devices.
