Development of Instrumentation for Research on Magnetic Thin Films and Microstructures

该奖项部分支持独特仪器的开发，用于合成横向约束薄膜和多层磁性材料和微结构，以及研究结构中的新型磁性现象。新仪器结合了最先进的薄膜生长和表征能力，接触掩模和聚焦离子束技术，能够在薄膜中创建亚微米结构。新仪器为德克萨斯大学现有的研究项目增加了重要的能力，这些研究项目探索薄膜磁学、介观物理、微磁学和磁输运现象。基于该仪器的新功能，需要探索的科学问题包括：1)微磁现象，包括超薄膜和微米尺度超薄膜结构中的磁畴性质；2)故意诱导衬底粗糙度（原子步长）和薄膜厚度变化对薄膜和薄膜微结构的磁畴和相关性能（包括矫顽力和各向异性）的影响；3)有限尺寸尺度效应、临界行为、交换耦合和动力学性质；4)与多层膜和多层基微结构相关的磁输运和相关磁现象。该仪器设计的一个重要特点是独特地结合了材料生长和微结构制造能力、材料表征工具和磁敏感探头，可以单独使用，也可以作为一个集成系统使用。该仪器由三个耦合子系统组成：1)薄膜生长和表征室，包括多细胞分子束外延（MBE）和实时生长监测工具，包括反射高能电子衍射（RHEED）和俄歇电子能谱（AES）；低能电子衍射（LEED），包括高分辨率斑点轮廓分析能力；2)建立磁光克尔效应（MOKE）偏振计，用于高空间分辨率扫描测量和磁滞动力学分析；3)高分辨率扫描电镜和自旋极化分析（SEMPA）仪器。SEM/SEMPA仪器配置为接受聚焦离子束（FIB）柱来磨微结构，同时使用SEM查看过程。该系统集成了闸阀和气闸室，允许SEMPA/MOKE子系统或MOKE/薄膜生长子系统独立使用。这种仪器有可能促进对薄膜磁性结构的基本认识和理解。这种结构具有很大的器件应用潜力，可以带来磁性器件技术的突破。

9704222 Erskine This award partially supports the development of unique instrumentation for synthesizing laterally constrained thin film and multilayer magnetic materials and microstructures and for studying novel magnetic phenomena in the structures The new instrument incorporates state-of-the-art thin film growth and characterization capabilities, contact mask and focused ion beam technology capable of creating submicron structures in the films, and complementary high spatial resolution magnetic sensitive spectroscopy/microscopy probes The new instrumentation adds important capabilities to existing research programs of several faculty at The University of Texas which explore thin film magnetism, mesoscopic physics, micromagnetics and magneto-transport phenomena. Scientific issues to be explored based on new capabilities of the instrument include 1) micromagnetic phenomena including properties of magnetic domains in ultrathin films and patterned micron-scale ultrathin film structures; 2) the effects of deliberately induced substrate roughness (atomic steps) and film thickness variations on magnetic domains and related properties including coercive forces and anisotropy of thin films and thin film based microstructures; 3) finite size scaling effects, critical behavior, exchange coupling and dynamical properties of well characterized multilayer and microstructured magnetic systems, and 4) magneto-transport and related magnetic phenomena associated with multilayer films and multilayer- based microstructures. An important feature of the instrument design is the unique combination of materials growth and microstructure fabrication capabilities, materials characterization tools and magnetic sensitive probes which can be used separately or as an integrated system. The instrument consists of three coupled subsystems 1) a thin film growth and characterization chamber incorporating multicell molecular beam epitaxy (MBE) with real-time growth monitoring tools inclu ding Reflection High Energy Electron Diffraction (RHEED) and Auger Electron Spectroscopy (AES); Low Energy Electron Diffraction (LEED) including high resolution spot profile analysis capability; 2) a Magneto-Optic Kerr Effect (MOKE) polarimeter set up for high spatial resolution scanning measurements as well as analysis of hysteresis dynamics; and 3) a high resolution Scanning Electron Microscope with Spin Polarization Analysis (SEMPA) instrument. The SEM/SEMPA instrument is configured to accept a Focused Ion Beam (FIB) column to mill microstructures while viewing the process using SEM. The system is integrated with gate valves and air lock chambers permitting the SEMPA/MOKE subsystem or the MOKE/film growth subsystem to be used independently. %%% This instrumentation has the potential to advance the fundamental knowledge and understanding of thin-film magnetic structure. Such structures have great potential for device applications, which can produce breakthroughs in magnetic device technology.