U.S.-Egypt Cooperative Research: Size and Shape Dependence of Exchange Bias in Ferromagnetic/Antiferromagnetic Nanoparticles For High Density Data Storage Media

0710537罗斯描述：该项目支持马萨诸塞州剑桥市马萨诸塞州理工学院材料科学工程系卡罗琳·罗斯博士的合作研究。 合作科学家是埃及开罗国家研究中心的Emad Girgis博士。 他们计划研究用于高密度数据存储介质的铁磁/反铁磁纳米颗粒中交换偏置的大小和形状依赖性。智力优势：交换偏置是指磁性材料的磁滞回线沿着磁场轴的偏移，该偏移是由耦合到反铁磁材料引起的。这种系统的例子包括氧化的钴颗粒，其中钴氧化物表面层是反铁磁体，以及薄膜材料，例如用IrMn钉扎的Co，其用于生产被称为自旋阀的传感器器件，用于磁读取头或磁随机存取存储器。自发现以来的40多年里，交换各向异性现象已成为信息存储技术中重要应用的基础。这个项目的智力价值是更好地理解纳米磁性材料中的交换偏置。该项目研究了交换偏置对薄膜和纳米颗粒的纳米级磁性结构的影响，并涉及与材料磁性能相关的物理和磁性微观结构的表征。更广泛的影响：该项目促进了美国研究人员和埃及研究人员之间的合作。它使初级科学家和高级科学家能够会面，交换样品，并对彼此的材料进行测量。两个研究组的材料合成和测量工具是互补的，这一合作项目将使两个研究组能够以协同的方式从彼此的专业知识中受益。该项目得到了美国-埃及联合基金项目的支持，该项目为两国的科学家和工程师提供赠款，以开展这些合作活动。

0710537RossDescription: This project supports collaborative research by Dr. Caroline Ross, Department of Materials Science & Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts. The collaborating scientist is Dr. Emad Girgis, National Research Center, Cairo, Egypt. They plan to study size and shape dependence of exchange bias in ferromagnetic/antiferromagnetic nanoparticles for high density data storage media. Intellectual Merit: Exchange bias refers to the shift of the hysteresis loop of a magnetic material along the magnetic field axis caused by coupling to an antiferromagnetic material. Examples of such systems include oxidised cobalt particles where the cobalt oxide surface layer is the antiferromagnet, and thin film materials such as Co pinned with IrMn, which are used to produce sensor devices known as spin valves, used in magnetic read heads or magnetic random access memories. In the more than 40 years since its discovery, the phenomenon of exchange anisotropy has become the basis for important applications in information storage technology. The intellectual merit of this project is to understand better exchange bias in nanoscale magnetic materials. The project examines the effect of exchange bias in nanoscale magnetic structures of thin films and nanoparticles, and involves characterization in terms of the physical and magnetic microstructure which will be correlated to the magnetic performance of the materials.Broader Impact: This project facilitates collaboration between a group of researchers in the US and a group in Egypt. It enables both the junior scientists and senior scientists to meet, exchange samples, and perform measurements on each other''s materials. The materials synthesis and measurement tools available to each group are complementary, and this collaborative program will enable both groups to benefit from the expertise of each other in a synergistic way.This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.