CAREER: Magnetic Domain Imaging in Nanostructured Ferromagnets

这是一个职业项目，致力于开发一种被称为高分辨率BIT方法(HRBM)的技术，并将其应用于纳米结构材料中的铁磁性研究。HRBM方法中经典使用的胶体磁流体将被溅射或蒸发到惰性大气中的磁性材料所取代，以产生纳米尺寸的粒子。粒子被沉积在磁性材料上，并沿着磁区壁聚集，从而允许对磁区进行可视化。扫描电子显微镜(SEM)用来对胶体装饰材料进行成像。这项新技术将应用于具有巨磁电阻(GMR)的铁磁性颗粒固体的研究。在GMR材料中意外观察到的磁区的性质，人们对此知之甚少。HRBM还将用于研究在制备具有商业意义的NdFeB硬磁材料过程中出现的不均匀现象。彻底了解导致不均匀的过程可能会改善这些材料的性能。该项目的教育部分涉及开发和传播即时教学系统。这是一种新颖的教学工具，包括使用网络交付预备作业，学生在每节课前回答这些作业。然后，教师将学生的反应用于备课并作为课堂讨论的基础。这是一个致力于磁性材料研究和开发新的教学方法的职业项目。磁性研究部门将开发和改进一种新的方法，将纳米磁性颗粒涂层喷洒到磁性材料上。小粒子在这些材质中沿着颗粒边界聚集，提供了一种可视化和映射这些域的方法。该项目将研究磁记录应用中发现的巨磁电阻(GMR)材料等磁性材料，以及具有商业意义的高强度钕铁硼硬磁体。教育部分涉及即时教学系统技术的开发。这一新颖的教学工具包括使用万维网交付预备作业，学生在每节课前回答。然后，教师将学生的反应用于备课并作为课堂讨论的基础。这导致了学生和教师之间有效和加强的互动。

This is a CAREER project is devoted to the development of a technique known as the High Resolution Bitter Method (HRBM), and its application to the study of ferromagnetism in nanostructured materials. The colloidal ferrofluids used classically in the HRBM method will be replaced by sputtering or evaporation of magnetic material into an inert atmosphere to produce nanometer-sized particles. The particles are deposited on magnetic materials and aggregate along domain walls thus allowing a visualization of the domains. A scanning electron microscope (SEM) used to image the colloidially decorated materials. The new technique will be applied to the study of ferromagnetic granular solids which exhibit Giant Magneto Resistance (GMR). The nature of the domains, unexpectedly observed in GMR materials, is poorly understood. the HRBM will also be used to study nonuniformities that occur in the preparation of the commercially important NdFeB hard magnetic materials. A thorough understanding of the process leading to nonuniformities may lead to improvements in the properties of these materials. The educational component of this project involves the development and dissemination of the Just-in-Time Teaching system. This is a novel pedagogical tool that includes the use of the web to deliver preparatory assignments that students answer just before each class. The students' responses are then used by faculty for lecture preparation and as a basis for classroom discussion. This leads to an effective and enhanced interaction between students and teacher.%%%This is a CAREER project devoted to the study of magnetic materials, and to development of new teaching methods. The magnetic research component will develop and refine a new method to spray a coating of nanometer sized magnetic particles on to magnetic materials. The small particles aggregate along grain boundaries in these materials, providing a means to visualize and map these domains. The project will investigate magnetic materials such as the Giant Magneto Resistive (GMR) materials found in the magnetic recording applications, as well as the commercially important high-strength neodymium-iron-boron hard magnets. The educational component involves development of the Just-in-Time Teaching system techniques. This novel pedagogical tool includes the use of the world wide web to deliver preparatory assignments that students answer just before each class. The students' responses are then used by faculty for lecture preparation and as a basis for classroom discussion. This leads to an effective and enhanced interaction between students and teacher.