Collaborative Research: Ultrafast Laser Study and Modification of Anisotropy in Ferromagnetic Thin Films

*******非技术摘要*******该奖项支持一个研究项目，该项目将应用全光超快泵浦探测激光技术来研究对计算机技术很重要的工程磁性薄膜的特性。在超快泵浦-探针技术中，脉冲激光束（脉冲持续时间小于万亿分之一秒）被分成两条路径：泵浦和探针。泵浦光束扰动所研究薄膜的磁性能，而探针光束在时间上延迟，在泵浦激励一段时间后测量薄膜的状态。这种技术类似于频闪摄影，使我们能够在最快的时间尺度上拍摄磁性的“快照”。这项工作的目标是确定和控制铁磁薄膜中切换的最终时间尺度，这对于计算机系统中数据存储，操作和检索的最终速度至关重要。这项工作将为研究生和本科生提供学习磁性薄膜的合成和表征技术以及最新的超快激光光学技术的机会。调查人员还在为公众举办有关技术主题的讲座。*******技术摘要*******该奖项支持威廉玛丽学院和托莱多大学的一名研究人员之间的合作。本实验项目将应用全光超快泵浦探测激光技术研究工程铁磁多层薄膜的各向异性和磁化动力学。薄膜磁特性的各向异性是决定磁性材料在计算机应用中的有用性的一个重要性质。例如，各向异性影响自旋动力学，可以决定磁性材料的最终读/写时间。超快激光技术允许实时测量磁化动力学和各向异性。在这个项目中，一名研究人员将制作具有大各向异性的磁性薄膜，而另一名研究人员将专注于激光测量。除了研究某些特殊材料体系的各向异性和加强基于超快激光的各向异性测量技术的使用外，研究人员还将使用超快激光脉冲永久诱导各向异性。这项工作将为研究生和本科生提供学习磁性薄膜的合成和表征技术以及最新的超快激光光学技术的机会。

*******NON-TECHNICAL ABSTRACT*******This award supports a research project that will apply all-optical ultrafast pump-probe laser techniques to study properties of engineered magnetic thin films important for computer technology. In the ultrafast pump-probe technique, a pulsed laser beam (pulses lasting less than one trillionth of a second) is split into two paths: a pump and probe. The pump beam perturbs the magnetic properties of the thin film under study, while the probe beam, delayed in time, measures the state of the film some time after the pump excitation. This technique, analogous to strobe photography, allows us to take "snapshots" of magnetic properties on the fastest timescales. The goal of this work is to determine and control the ultimate time scale of switching in ferromagnetic thin films, important for the ultimate speed of data storage, manipulation and retrieval in computer systems. This work will provide graduate and undergraduate students opportunities to learn synthesis and characterization techniques for magnetic thin films as well as state of the art ultrafast laser optical techniques. The investigators are also developing lectures on technological subjects for the general public. *******TECHNICAL ABSTRACT*******This award supports a collaboration between a researcher at the College of William and Mary and another at the University of Toledo. The experimental project will apply all-optical ultrafast pump-probe laser techniques to study anisotropy and magnetization dynamics in engineered ferromagnetic multilayer thin films. Anisotropy in the magnetic characteristics of thin films is an important property that determines the usefulness of magnetic materials in computer applications. For example, anisotropy affects the spin dynamics and can determine the ultimate read/write time for magnetic materials. Ultrafast laser techniques allow for the measurement of magnetization dynamics and anisotropic properties directly in real time. In this project, one investigator will produce magnetic thin films with large anisotropic properties, while another will focus on the laser measurements. Besides studying anisotropy in some unique material systems and enhancing the use of ultrafast laser-based techniques for the measurement of anisotropy, the investigators will also use ultrafast laser pulses to permanently induce anisotropy. This work will provide graduate and undergraduate students opportunities to learn synthesis and characterization techniques for magnetic thin films as well as state of the art ultrafast laser optical techniques.