Study of the dynamic properties of magnetic skyrmions using diffractive ferromagnetic resonance

磁性Skyrmions，即，在手征晶格磁体和工程异质结构中已经发现了以量子化拓扑不变量为特征的涡旋状旋转自旋纹理。外场作用下的磁有序系统动力学是一个非常重要的问题，因为它们具有量子涌现特性，同时由于它们的拓扑保护作用，它们在自旋电子器件中的技术应用也是一个非常重要的问题。一个例子是三种不同的动力学模式的skyrmion晶格中的手征晶格磁铁Cu2OSeO3。除了作为一个良好表征的模型系统之外，这种绝缘skyrmion材料还具有多铁性，从而导致具有应用潜力的自旋诱导铁电性，例如，微波二极管该项目的重点是详细了解skyrmion系统的磁化动力学，这为skyrmion在快速开关器件中的实际应用铺平了道路。单个Skyrmion涡旋的直径约为60 nm。如此小的长度尺度需要高的空间分辨率，因此大多数磁显微镜技术是不合适的。REXS可用于通过使用具有调谐到Cu L边缘的光子能量的偏振软X射线来确定磁有序。由于入射X射线的极化性质，REXS对磁化矢量的三个分量具有不同的灵敏度。REXS在Skyrmions的研究中具有独特的优势：它是元素选择性的，对磁序具有非常高的灵敏度，提供可变的采样区域，并允许快速有效的数据采集。另一方面，铁磁共振是研究动态磁特性的有力工具，如共振模式和阻尼特性，以及各向异性。这些互补的技术将被应用于研究各种自旋结构的自旋动力学。该项目是与钻石光源，特别是Gerrit货车der Laan教授小组的共同努力。通过我们的EPSRC skyrmion赠款与Western Digital，Hitachi，IBM，Samsung和Seagate Technology建立了行业联系。该项目与EPSRC的研究领域“凝聚态物质：磁性和磁性材料”和“自旋电子学”保持一致。

Magnetic skyrmions, i.e., vortex-like swirling spin textures characterized by a quantized topological invariant, have been found in chiral-lattice magnets and engineered heterostructures. Their dynamics under external fields is an issue of vital importance for both fundamental science, owing to their emergent quantum properties, and technological applications in spintronic devices owing to their topological protection.The aim of the Project is to use ferromagnetic resonance (FMR) and resonant elastic soft x-ray scattering (REXS) to study long-range ordered magnetic systems and their dynamic properties. One example are the three different dynamical modes of the skyrmion lattice in the chiral-lattice magnet Cu2OSeO3. Apart from being a well-characterised model system, this insulating skyrmion material has also multiferroic properties leading to spin-induced ferroelectricity with an application potential as, e.g., microwave diodes. The Project is focused on gaining understanding of the magnetisation dynamics of skyrmion systems in great detail, which paves the way for the practical use of skyrmions in fast-switching devices. An individual skyrmion vortex has the diameter of around 60 nm. Such a small length scale requires high spatial resolution, therefore most of the magnetic microscopy techniques are unsuitable. REXS can be used to characterise the magnetic ordering by using polarized soft x-rays with the photon energy tuned to the Cu L edge. Due to the polarized nature of the incidence x-rays, REXS has different sensitivities to the three components of the magnetization vector. REXS has unique advantages for the study of skyrmions: it is element-selective, has a very high sensitivity for magnetic order, provides a variable sampling area, and allows for fast and efficient data acquisition. FMR, on the other hand, is a powerful tool for the study of dynamic magnetic properties such as the resonance modes and damping characteristics, as well as anisotropies. These complementary techniques will be applied to study the spin dynamics of various spin structures. This project is a joint effort with the Diamond Light Source, and in particular with the group of Prof Gerrit van der Laan. Industrial contacts exist via our EPSRC skyrmion grant with Western Digital, Hitachi, IBM, Samsung, and Seagate Technology.This project aligns with EPSRC's research areas "Condensed Matter: Magnetism and Magnetic Materials" and "Spintronics".