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。这种可调性导致它们在广泛的局部领域中使用，包括手性磁性材料中的skyrmions，合成反铁磁体和自旋电子器件。磁性多层材料为超快功能器件的发展提供了多种机会，然而，迄今为止，一种有效的方法来确定动态特性作为这种堆叠深度的函数仍然是难以捉摸的。最近，我们提出了一种新的技术，即反射铁磁共振（RFMR），它为充分探索磁性多层系统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工作基础上，使用x射线磁圆二色（XMCD）和x射线检测铁磁共振（XFMR）来探索磁性材料系统中元素特定的磁化动力学。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。这是第一次允许对“隐藏”层的磁化动力学进行选择性探测，这是其他铁磁共振方法无法达到的。该项目旨在全面建立钻石的RFMR技术，充分利用钻石的设施，其独特的技术机会和光束线支持，以及射频和光谱专业知识。为了准备该项目，并在总体上展示RFMR的巨大潜力，我们测量了[CoFeB/MgO/Ta]4多层中磁化动力学的深度依赖性，这对其他技术来说是“不可见的”，揭示了新的动态行为。在第一步，学生将成长和探索合成反铁磁体，旨在解开磁性粒子动力学。该项目是与钻石光源，特别是与Gerrit van der Laan教授小组的联合项目。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”相一致。

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".