CAREER: Nonlinear Optical Studies of Spin and Magnetization Dynamics in Ferromagnetic Multilayers

这一学院早期职业发展(CALEAR)项目旨在加强威廉与玛丽学院现代光学和凝聚态物理领域的研究和教育。本研究的目的是应用超快泵浦-探测激光光谱的最新技术，包括频率相关和时间分辨的磁光克尔效应和磁化诱导的二次谐波产生，来回答有关铁磁薄膜多层膜的自旋极化和自旋和磁化动力学的问题。这种多层膜在技术应用上显示出巨大的前景，但受到对电子自旋寿命以及自旋散射和自旋翻转来源的不完全了解的限制。将要探索的系统包括显示巨磁电阻的磁性多层膜、半金属材料和金属/半导体系统。这项工作将继续开发无损、快速和直接的非线性光学技术来测量对自旋设备至关重要的参数。这个项目的教育目标是开发一系列实验室模块，用于向学院的本科生介绍现代光学和材料物理，并用于当地社区的外展计划。%这个学院早期职业发展(CALE)项目旨在加强威廉和玛丽学院现代光学和材料物理领域的研究和教育。在研究中，超快脉冲激光技术(激光脉冲持续时间小于万亿分之一秒)将被用来测量薄膜铁磁多层膜的磁性如何随时间演变。在这些技术中，一个“泵浦”光束被用来激发被研究的材料，而另一个脉冲光束则“探测”或在稍后的时间拍摄系统状态的快照。例如，这种技术已经成功地用于研究发生时的化学反应，并且直到最近才被应用于磁性材料。研究磁过程的终极速度以及决定磁性薄膜的磁性和电学特性的因素对于电子和磁性设备的设计极其重要，如硬盘驱动器读取头、非易失性计算机存储器和基于电子自旋的新一代计算机设备(称为自旋电子学或磁电子学)。该项目的教育目标是开发一系列动手实验模块，用于向学院的本科生介绍现代光学和材料物理，并用于当地社区的外联计划。

This Faculty Early Career Development (CAREER) project seeks to enhance research and education in the areas of modern optics and condensed matter physics at the College of William and Mary. The objective in research is to apply the newest techniques in ultrafast pump-probe laser spectroscopy, including frequency-dependent and time-resolved magneto-optical Kerr effect and magnetization-induced second harmonic generation, to answer questions regarding spin polarization and spin and magnetization dynamics in ferromagnetic thin film multilayers. Such multilayers are showing great promise in technological applications, but are limited by incomplete knowledge of electron spin lifetimes and the sources of spin scattering and spin-flipping. Systems to be explored include magnetic multilayers displaying giant magnetoresistance, half-metallic materials and metal/semiconducting systems. This work will continue to develop non-destructive, fast and straightforward nonlinear optical techniques to measure parameters crucial for spin-based devices. The educational goal of this project is the development of a series of laboratory modules which will be used to introduce modern optics and the physics of materials to undergraduates at the College as well as be used in outreach programs to the local community.%%%This Faculty Early Career Development (CAREER) project seeks to enhance research and education in the areas of modern optics and the physics of materials at the College of William and Mary. In research, ultrafast pulsed laser techniques (with laser pulses less than one-trillionth of a second in duration), will be used to measure how the magnetic properties of thin-film ferromagnetic multilayers evolve in time. In these techniques, a "pump" beam is used to excite the material under study while a second pulsed beam "probes" or takes a snapshot of the state of the system later in time. Such techniques have been successfully used, for example, to study chemical reactions as they occur, and have only recently been applied to magnetic materials. The study of the ultimate speed of magnetic processes and what determines the magnetic and electrical properties of magnetic thin films is extremely important for the design of electronic and magnetic devices such as hard drive read heads, nonvolatile computer memory and the next generation computer devices based on electron spin (dubbed "Spintronics" or Magnetoelectronics"). The educational goal of this project is the development of a series of hands-on laboratory modules which will be used to introduce modern optics and the physics of materials to undergraduates at the College as well as be used in outreach programs to the local community.***