铁磁性纳米片间相互作用对其微波磁性的影响

Influences of the interaction of ferromagnetic nanosheets on their microwave magnetic properties

在铁磁性元素中,交换能、偶极能和各向异性能之间存在复杂的竞争,因此,这种结构化介质的静态和动态性能与构成材料的固有磁特性,各个元素的形状和尺寸等有着密切的关系.这些多个自由度提供了对于通常未构图的磁性薄膜不可达到的新性能.本文通过将所研究的系统划分成立方体网格的三维阵列来对其进行建模,研究具有不同相对位置、纳米片间距、磁各向异性方向的两矩形铁磁性纳米片的微波磁性能.研究发现:与单个矩形铁磁性纳米片相比,具有不同相对位置、纳米片间距的两矩形铁磁性纳米片共振峰频率分布发生变化;当两矩形纳米片磁各向异性方向所呈角度由0°增加到30°时,其磁性质没有明显变化,而从30°到90°时,其磁性质对磁各向异性方向变化比较敏感.通过调控纳米片的相对位置、纳米片间距以及磁各向异性方向可以制备具有良好性能的吸收材料.

Submicron ferromagnetic elements have received extensive attention due to their wide applications in magnetic recording,microwave devices and advanced magnetic absorbing material.The static and dynamic properties of such structured media depend intimately on various aspects such as the intrinsic magnetic characteristics of constitutive materials,and the shape and size of the individual elements,and so on.These multiple degrees of freedom provide a new performance that can not be achieved for the normally unstructured magnetic films.In this paper,we divide the system into three dimensional array of cubic grids to model it,and study the microwave magnetic properties of two rectangular ferromagnetic nanosheets with different relative positions,nanosheet spacing and magnetic anisotropy direction.Compared to the single rectangular ferromagnetic nanosheets,the resonance peak frequency distribution of the two rectangular ferromagnetic nanosheets with different relative positions and the particle spacing were found to change.When the angle of the magnetic anisotropy of the two rectangular nanosheets was increased from 0 to 30 degrees,the magnetic properties of the films was not changed significantly,but the magnetic properties were sensitive to the variation of the magnetic anisotropy direction in the range from 30 to 90 degrees.Therefore,we can prepare a good performance of the absorption material by adjusting the relative position,the particle spacing and the direction of the magnetic anisotropy.