Reconfigurable wave band structure of an artificial square ice
Reconfigurable wave band structure of an artificial square ice
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DOI：
10.1103/physrevb.93.134420
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发表时间：
2016-04-18
影响因子：
3.7
通讯作者：
Heinonen, Olle
中科院分区：
文献类型：
--
作者：
Iacocca, Ezio;Gliga, Sebastian;Heinonen, Olle
人造方形冰是由排列在二维方形晶格位置上的磁性纳米元素组成的结构，每个顶点有四个相互作用的磁性元素，导致几何挫败。使用半解析方法，我们表明方形冰表现出丰富的自旋波带结构，该结构可以通过外部磁场和单个元素的磁化配置进行调节。内部自由度可以产生平衡状态，元件边缘处的弯曲磁化导致特征激励；在存在静磁相互作用的情况下，它们形成类似于半导体中的杂质带的单独带。全尺寸微磁模拟证实了我们的半解析方法。我们的研究结果表明，人造方冰可以被视为可重构和可调的镁子晶体，可以用作纳米尺度上基于自旋波的应用的超材料。
Artificial square ices are structures composed of magnetic nanoelements arranged on the sites of a two-dimensional square lattice, such that there are four interacting magnetic elements at each vertex, leading to geometrical frustration. Using a semianalytical approach, we show that square ices exhibit a rich spin-wave band structure that is tunable both by external magnetic fields and the magnetization configuration of individual elements. Internal degrees of freedom can give rise to equilibrium states with bent magnetization at the element edges leading to characteristic excitations; in the presence of magnetostatic interactions these form separate bands analogous to impurity bands in semiconductors. Full-scale micromagnetic simulations corroborate our semianalytical approach. Our results show that artificial square ices can be viewed as reconfigurable and tunable magnonic crystals that can be used as metamaterials for spin-wave-based applications at the nanoscale.