Neutron Scattering Studies of Ferromagnetic Semiconductor Superlattices Based on III-V and IV-VI Compounds

9972586 giebultowicz这是一个凝聚态物理项目，使用中子衍射和反射来研究由铁磁（FM）和非磁性半导体组成的新型异质结构和超晶格。衍射测量提供了关于自旋结构和层间磁相关性的详细信息。含有调频成分的半导体纳米结构在实际应用中最具吸引力。然而，直到最近，只有由具有强反铁磁（AFM）相互作用的材料制备的多层材料可用。这一领域的一个突破是基于Ill-V半导体化合物制备新的外延调频薄膜和异质结构。这些GaAsMn异质结构和其他具有铁磁耦合潜力的材料将作为该项目的一部分进行研究。所有的衍射和反射率测量将在盖瑟斯堡NIST的中子研究中心进行。该研究将为与该项目相关的博士后和研究生提供良好的教育培训。磁性半导体显示出一系列不同寻常的特性，这些特性具有重大的基础意义，并且在未来技术中具有潜在的用途。该项目将利用中子散射作为一种强有力的工具来研究由半导体和磁性材料组成的磁性超晶格。中子技术可以测定组成超晶格的原子层中的磁相互作用和自旋结构。这项工作将集中在相互作用是铁磁性的材料上，导致材料中的大磁矩，因此显示出实际应用的潜力。自旋电子学领域的实际应用取决于材料中的电输运是由磁相互作用调制的这一事实，如巨磁阻现象。一些待研究的材料，如砷化镓铁磁体，与现有的半导体技术兼容，并可能导致实用的设备。参与这项工作的学生和博士后在基础物理这一令人兴奋的领域获得了良好的训练，这在未来的实际应用中具有很大的潜力。所有的衍射和反射率测量将在盖瑟斯堡NIST的中子研究中心进行。医学博士。

9972586GiebultowiczThis is a condensed matter physics project that uses neutron diffractometry and reflectometry to investigate novel heterostructures and superlattices (SLs) composed of ferromagnetic (FM) and nonmagnetic semiconductors. Diffraction measurements provide detailed information about the spin structures and about the interlayer magnetic correlations in the SLs. Semiconducting nanos-tructures containing FM constituents are the most attractive ones for practical applications. However, until recently only multilayers prepared from materials with strongly antiferromagnetic (AFM) interactions were available. A break-through in this area has been the preparation of new epitaxial FM films and heterostructures based on the Ill-V semiconducting compounds. These GaAsMn heterostructures and additional materials with potential to exhibit ferromagnetic couplings will be investigated as part of this project. All diffraction and reflectivity measurements will be carried out at the Center for Neutron Research at NIST, Gaithersburg., MD. The research will provide excellent education training for the post-doctoral associate and the graduate students associated with the project.%%%Magnetic semiconductors show a range of unusual properties that are of great fundamental interest as well as of potential use in future technologies. This project will use neutron scattering as a powerful tool to investigating magnetic superlattices composed of semiconducting and magnetic materials. The neutron technique allows a determination of the magnetic interactions and spin structures in the atomic layers composing the superlattices. The work will focus on materials where the interactions are ferromagnetic, lead to large magnetic moments in the materials, and hence show potential for practical applications. The practical applications or spintronics field depend on the fact that the electrical transport in the materials is modulated by the magnetic interactions, as in the phenomenon of giant magneto resistance. Some of the materials to be studied, the GaAsMn ferromagnet, are compatible with existing semiconductor technologies, and may lead to practical devices. The students and post-doc involved in this work obtain excellent training in an exciting area of fundamental physics, which has great potential for future practical applications. All diffraction and reflectivity measurements will be carried out at the Center for Neutron Research at NIST, Gaithersburg., MD.