Materials World Network: A Study of Spin Dynamics in Fe/CoO/MgO(001) and Fe/NiO/MgO(001) Using Time-Resolved and Element-Specific XMCD and XMLD

技术摘要：此次材料世界网络合作将开发一项研究计划，在劳伦斯伯克利国家实验室的先进光源（ALS）上对磁性纳米结构中的自旋动力学进行时间分辨和元素特异性测量。通过分子束外延（MBE）在MgO（001）衬底上生长铁磁/反铁磁（FM/AFM） Py/CoO和Py/NiO双层膜，并通过共面波导样品设计将2或4GHz微波传递到样品中以产生Py层的铁磁共振（FMR）。通过将微波源与ALS加速器频率同步，研究小组将对Py自旋动力学进行时间分辨和特定元素的x射线磁圆二色性（XMCD），对CoO或NiO自旋动力学进行x射线磁线性二色性（XMLD）。这项研究将涉及美国加州大学伯克利分校和英国埃克塞特大学交换学生的密切合作，以及美国ALS和英国Diamond Source之间的关键技术信息。摘要：随着磁性器件的性能越来越快，自旋动力学在纳米结构中变得越来越重要。特别是在纳秒或千兆赫的范围内设置了自旋过程在自旋开关中开始支配畴壁运动的临界时间尺度。这个材料世界网络合作研究项目将对FM/AFM纳米结构在GHz范围内的自旋动力学有一个基本的了解。为了实现这一目标，需要美国、英国和同步加速器专家之间的合作努力。研究结果将有助于理解重要的ns时间范围内的自旋动力学，为未来的自旋电子学器件提供指导。通过交流项目，研究生将获得最前沿的现代实验技术的培训，这对他们未来在学术、工业和政府工作的职业生涯至关重要。本项目由凝聚态物理项目和材料研究部特别项目办公室支持。

Technical Abstract: This Materials World Network collaboration will develop a research program to perform time-resolved and element-specific measurement on spin dynamics in magnetic nanostructures at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory. Ferromagnetic/Antiferromagnetic (FM/AFM) Py/CoO and Py/NiO bilayers will be grown on MgO(001) substrate by Molecular Beam Epitaxy (MBE) and 2 or 4GHz microwaves will be delivered to the sample through coplanar waveguide sample design to generate ferromagnetic resonance (FMR) of the Py layer. By synchronizing the microwave source with the ALS accelerator frequency, the research team will perform time-resolved and element-specific X-ray Magnetic Circular Dichroism (XMCD) on the Py spin dynamics and X-ray Magnetic Linear Dichroism (XMLD) on the CoO or NiO spin dynamics. The research will involve a close collaboration by exchanging students between UC-Berkeley at US and Exeter Univ. at UK, as well as critical technical information between ALS in US and Diamond Source in UK. Non-Technical Abstract: As magnetic devices perform faster and faster, spin dynamics becomes more and more important in nanostructures. In particular, nanosecond or GHz range sets a critical time scale beyond which spin procession starts domination domain wall motion in spin switching. This Materials World Network collaborative research program will develop a basic understanding of the spin dynamics right in the GHz range in FM/AFM nanostructures. In order to achieve this goal, collaborative effort is needed among US, UK, and Synchrotron expertise. Results of the research will lead to an understanding of the spin dynamics in the important ns time range to provide guidance for future spintronics devices. Graduate students will receive training at the cutting edge of modern experimental techniques through exchange program, which is crucial for their future careers in academic, industrial, and government jobs.This project is supported by the Condensed Matter Physics Program and the Office of Special Programs in the Division of Materials Research.