Spin-wave nonreciprocity and formation of lateral standing spin waves in CoFeB/Ta/NiFe meander-shaped films
Spin-wave nonreciprocity and formation of lateral standing spin waves in CoFeB/Ta/NiFe meander-shaped films
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CoFeB/Ta/NiFe 曲折形薄膜中自旋波非互易性和横向驻自旋波的形成
DOI：
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发表时间：
2022
影响因子：
3.2
通讯作者：
F. Ciubotaru
中科院分区：
文献类型：
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作者：
G. Gubbiotti;A. Sadovnikov;S. Sheshukova;E. Beginin;S. Nikitov;G. Talmelli;C. Adelmann;F. Ciubotaru
研究3D周期性结构中的自旋波（SW）传播为连接置于磁振子电路不同层上的功能单元开辟了新的可能性。在通往3D磁振子的道路上，主要的挑战是制造具有纳米精度控制几何形状和材料成分的大规模3D磁性结构。在这项工作中，我们研究了依赖于Ta间隔厚度的磁振子带结构，测量布里渊光散射光谱，CoFeB/Ta/NiFe的曲折形双层制在预先图案化的Si衬底上的厚度步骤为50 nm。传播和固定SW模式进行观察。虽然色散模式的频率略微取决于Ta间隔物的厚度，但通过增加Ta厚度，光谱的最低频率范围中的三个固定模式的频率位置显著增加。微磁学计算表明，三个固定模式中的每一个都是由模式的双峰组成的，其频率分离，在每个双峰内，通过增加模式频率而增加。这种频率分离的起源归因于磁层之间的动态偶极耦合，其产生反向传播SW的显著频率非互易性。由于这些原因，所研究的结构提供了潜在的应用，作为非互易通用互连执行的频率选择制度的信号传播的磁振子电路。
Studying the spin-wave (SW) propagation in 3D periodic structures opens new possibilities for joining functional units placed on the different layers of the magnonic circuitry. In the path toward 3D magnonics, the main challenge is the fabrication of large-scale 3D magnetic structures with nanometric precision control of geometry and material composition. In this work, we study the dependence on the Ta spacer thickness of the magnonic band structure, measured by Brillouin light scattering spectroscopy, of CoFeB/Ta/NiFe meander-shaped bilayers fabricated on pre-patterned Si substrate with thickness steps of 50 nm. Both propagating and stationary SW modes are observed. While the frequency of the dispersive mode slightly depends on the Ta spacer thickness, the frequency position of the three stationary modes in the lowest frequency range of the spectra significantly increases by increasing the Ta thickness. Micromagnetic calculations indicate that each of the three stationary modes is composed of a doublet of modes whose frequency separation, within each doublet, increases by increasing the mode frequency. The origin of this frequency separation is ascribed to the dynamic dipolar coupling between the magnetic layers that generate a significant frequency nonreciprocity of counterpropagating SWs. For these reasons, the investigated structures offer potential application as the nonreciprocal versatile interconnections performing the frequency selective regimes of signal propagation in magnonic circuits.