Zhang Wanling, Zhang Jiaming, Wu Peng, Chai Guozhi, Huang Ran, Ma Fei, Xu Fangfang, Cheng Hongwei, Chen Yonghui, Ni Xia, Qiao Liang, Duan Jinglai
School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
Materials Research Center, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
ACS Appl Mater Interfaces. 2020 May 20;12(20):23340-23346. doi: 10.1021/acsami.0c04247. Epub 2020 May 11.
Magnetic nanostructures with conical shape are highly desired for pursuing extraordinary magnetic properties and microwave absorption. However, the fabrication of such nanostructures with controlled shape and size uniformities and alignment is not yet realized. Accordingly, the magnetic properties and their application as microwave absorber are not well understood. Here, we report on the first demonstration of controlled fabrication of soft magnetic nickel nanocone arrays with sharp geometry, large aspect ratio, uniform size, and parallel alignment. The imaginary part of the relative complex permeability shows multiband absorption in the 2-17 GHz range. Such an exceptional microwave absorption results from the uniform conical shape and size and the parallel alignment. The absorption mechanisms are discussed under the framework of natural resonance and exchange resonance. The natural resonance is dependent on the shape anisotropy and facilitated by the conical geometry. The exchange resonance is well explained by the observation of the bulk spin waves with exchange coupling at the tip of nanocones using the inelastic light scattering and is consistent with exchange theory predictions for the quantization of bulk spin waves. We expect that our work will shed light on the physical insights into the magnetic properties of nanocones and find great potential in applications of microwave absorption.
具有锥形形状的磁性纳米结构对于实现非凡的磁性能和微波吸收非常有吸引力。然而，尚未实现对这种具有可控形状、尺寸均匀性和排列的纳米结构的制造。因此，其磁性能及其作为微波吸收体的应用尚未得到很好的理解。在此，我们首次报道了对具有尖锐几何形状、大纵横比、均匀尺寸和平行排列的软磁镍纳米锥阵列的可控制造。相对复磁导率的虚部在2 - 17 GHz范围内表现出多频段吸收。这种优异的微波吸收源于均匀的锥形形状和尺寸以及平行排列。在自然共振和交换共振的框架下讨论了吸收机制。自然共振取决于形状各向异性，并由锥形几何结构促进。通过使用非弹性光散射观察纳米锥尖端具有交换耦合的体自旋波，很好地解释了交换共振，并且与体自旋波量子化的交换理论预测一致。我们期望我们的工作将为纳米锥磁性能的物理见解提供启示，并在微波吸收应用中发现巨大潜力。
