Acquisition of a Superconducting Magnetooptical Cryostat for Research and Student Training in Magnetoelectronic Materials

这是DMR材料研究仪器项目授予学院和威廉玛丽学院的奖项。该奖项是为了获得一台7特斯拉超导磁光低温恒温器，用于研究铁磁薄膜多层中的非线性磁光效应和磁输运。这种多层材料在技术应用方面显示出巨大的前景，但由于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而受到限制。该设备将被整合到超快泵浦探测激光光谱系统中，包括频率相关和时间分辨磁光克尔效应和磁化诱导的二次谐波产生，以回答有关自旋极化和自旋和磁化动力学的问题。该仪器还将用于培训学院的学生学习磁电子学的重要材料。这项由材料研究仪器授予威廉玛丽学院的奖项是为了获得一台低温、高磁场磁光低温恒温器，这将加强该学院在磁光学和磁输运领域的研究和教育。低温恒温器将被整合到一个系统中，该系统使用超快脉冲激光技术（激光脉冲持续时间小于万亿分之一秒）来测量薄膜铁磁多层的磁性如何随时间演变。在这些技术中，一个“泵浦”光束被用来激发所研究的材料，而另一个脉冲光束“探测”，或拍摄系统稍后状态的快照。例如，这些技术已经成功地用于研究化学反应的发生，但直到最近才被应用于磁性材料。研究磁性过程的最终速度以及决定磁性薄膜的磁性和电学性能的因素对于电子和磁性设备的设计非常重要，例如硬盘驱动器读磁头，非易失性计算机存储器和基于电子自旋的下一代计算机设备（称为“自旋电子学”或“磁电子学”）。

This is an award from the Instrumentation for Materials Research program in DMR to the College and William and Mary. The award is for acquisition of a 7 Tesla superconducting magnetooptical cryostat for the study of nonlinear magnetooptical effects and magnetotransport 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. This equipment will be incorporated into a system for 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. The instrument will also be used in training of students at the College to study materials important for magnetoelectronics. %%%This award from the Instruments for Materials Research to the College of William and Mary is for the acquisition of a low-temperature, high-field magnetooptical cryostat which will enhance research and education in the areas of magnetooptics and magnetotransport at the College. The cryostat will be incorporated into a system which uses ultrafast pulsed laser techniques (with laser pulses less than one-trillionth of a second in duration) 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").