Spin Wave Excitations in Periodic Nanostructures: Evolution from Periodical Perturbations to Magnonic Crystals

该项目的主要目标是研究从顶部具有周期性纳米结构的平板薄膜到全一维或二维磁子晶体的过渡区中的自旋波动力学。在磁子晶体中，由于双磁振子相互作用，模式分裂开始，最终导致带隙的打开。与全磁子晶体的研究相比，这一重要的跃迁机制目前还没有引起足够的重视。我们将利用宽带铁磁共振、时间分辨磁光克尔效应以及布里渊光散射等实验技术来研究这些纳米结构中的磁振子激发。在与P.Landeros教授(智利UTFSM)的理论小组的密切合作下，将应用和进一步发展现有的分析理论，以匹配和解释实验结果，例如个别模式的描述和意义，对避免频带交叉的发展的理解，以及对此类结构中增强的阻尼效应的洞察。

The main objective of the project is to investigate the spin wave dynamics in the transition regime from a flat film with periodical nanostructures on top towards a full 1D or 2D magnonic crystal. This regime exhibits the beginning of the mode splitting due to the two-magnon interaction, which in magnonic crystals finally lead to the opening of band gaps. Compared to studies on full magnonic crystals no attention has been paid to this important transition regime so far.Experimental techniques like broadband ferromagnetic resonance, time-resolved magnetooptical Kerr effect as well as Brillouin light scattering will be employed to study the magnon excitations in those nanostructures. In close collaboration with the theory group of Prof. P. Landeros (UTFSM Chile) already existing analytical theory will be applied and further developed to match and explain the experimental findings, e.g. descriptions and meaning of the individual modes, understanding of the development of the avoided band crossing, as well as insight into enhanced damping effects in such structures.