Reflectivity ferromagnetic resonance (RFMR) for layer-resolved dynamic study of multi-layered systems

项目描述：磁性多层系统是定制材料的一个主要例子，其功能可以通过先进的界面和层工程进行精确控制。这种可调性导致了它们在广泛的主题领域中的应用，包括手性磁性材料中的Skyrmions、合成反铁磁体和自旋电子器件。磁性多层膜为开发超快功能器件提供了不同的机会，然而，到目前为止，作为这种叠层深度的函数来确定动态特性的有效方法仍然难以捉摸。最近，我们提出了一种新的技术，反射式铁磁共振(RFMR)，它为全面探索磁性多层体系的磁化动力学提供了一条途径。RFMR技术建立在我们广泛和公认的使用X射线磁性圆二色谱(XMCD)和X射线检测铁磁共振(XFMR)来探索磁性材料系统中特定元素的磁化动力学的工作基础上。在这个项目中，结合软X射线共振反射率，我们扩展了这些技术，以获得作为深度函数的磁化动力学。该项目旨在全面建立钻石的RFMR技术，最大限度地利用钻石的设施、独特的技术机会和光束线支持，以及射频和光谱专业知识。为了准备这个项目，并展示RFMR的巨大潜力，我们测量了[CoFeB/MgO/Ta]4多层膜中磁化动力学的深度依赖关系，这对于其他技术来说是‘不可见的’，揭示了新的动态行为。在第一步中，学生将培养和探索合成反铁磁体，目标是揭开磁性天空米子动力学的面纱。这个项目是与钻石光源，特别是与格利特·范德兰教授团队的联合项目。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。

Project description:Magnetic multilayer systems are a prime example of tailored materials in which their functionalities can be precisely controlled through advanced interface and layer engineering. This tuneability has led to their use across a wide range of topical fields, including skyrmions in chiral magnetic materials, synthetic antiferromagnets, and spintronic devices. Magnetic multilayers offer diverse opportunities for the development of ultrafast functional devices, however, an efficient method for determining the dynamic properties as a function of depth throughout such stacks has so far remained elusive. Very recently, we presented a new technique, reflectometry ferromagnetic resonance (RFMR), which provides an avenue to fully explore the magnetization dynamics in magnetic multilayer systems.The RFMR technique builds on our extensive and well recognized work of using x-ray magnetic circular dichroism (XMCD) and x-ray detected ferromagnetic resonance (XFMR) to explore the element-specific magnetization dynamics in magnetic material systems. In this project, in combination with soft x-ray resonant reflectivity, we extend these techniques to gain access to the magnetization dynamics as a function of depth. For the first time, this allows for the selective probing of the magnetization dynamics in the 'hidden' layers, inaccessible to other ferromagnetic resonance methods.The Project aims at fully establishing the RFMR technique at Diamond, making optimal use of the facilities at Diamond, its unique technical opportunities and beamline support, as well as the RF and spectroscopy expertise. In preparation for the project, and to demonstrate the large potential of RFMR in general, we measured the depth-dependence of the magnetization dynamics in a [CoFeB/MgO/Ta]4 multilayer, which is 'invisible' to other techniques, exposing novel dynamic behaviour. In a first step, the student will grow and explore synthetic antiferromagnets, aiming at the unravelling of the magnetic skyrmion dynamics.This project is a joint project with the Diamond Light Source, and in particular with the group of Prof Gerrit van der Laan.This project aligns with EPSRC's research areas "Condensed Matter: Magnetism and Magnetic Materials" and "Spintronics".