Studies of Unusual Ferromagnetic Materials

这个个人研究者的研究项目包括两个与不寻常的铁磁性材料的特性相关的研究重点，其中磁性和电子特性是强耦合的。第一个研究重点将是研究“巨磁阻”钙钛矿锰矿中与相分离有关的现象。最近的实验和理论工作表明，本征磁电相分离是这些材料的一个重要的物理因素，研究将探讨由此产生的新现象。第二个研究重点将是研究铁磁性（Ga,Mn）As和MnAs薄膜的输运和磁性。这些材料（分别是半导体和金属）的基本物理将通过纯材料和将这些铁磁体与其他磁性和非磁性材料相结合的异质结构的磁性和磁输运研究来探索。该项目的教育部分将包括至少一名研究生的论文工作和本科生在实验室的积极参与。这些学生将获得知识和技能，将在未来的职业生涯中使用，无论是在学术界，工业或政府实验室。这个个人研究项目集中在两个不同的研究重点上，这些研究重点与不寻常的铁磁性材料的性质有关，即显示宏观磁矩。研究的特定材料特别有趣，因为它们的磁性与它们的电子特性密切相关，对这种耦合的基本理解的进步可能有助于“自旋电子”技术的应用，这种技术利用了磁性和电子特性的结合。第一个研究重点将是调查一类被称为“巨磁阻”钙钛矿锰矿的化合物中两种不同类型的磁性和电子相共存的现象。第二个研究重点将是研究铁磁性（Ga,Mn）As和MnAs薄膜的输运和磁性，这两种薄膜都可以在常用的半导体GaAs上外延生长，因此可能具有更直接的技术重要性。拟议研究的教育部分将包括至少一名研究生的论文工作和本科生在实验室的积极参与。这些学生获得的培训将对未来在工业、政府或学术界的职业生涯有价值

This individual investigator research project includes two research thrusts related to the properties of unusual ferromagnetic materials in which the magnetic and electronic properties are strongly coupled. The first research thrust will be an investigation of phenomena related to phase separation in the "colossal magnetoresistance" perovskite manganites. Recent experimental and theoretical work has indicated that intrinsic magnetoelectronic phase separation is an important element of the physics of these materials, and the research will investigate resultant novel phenomena. The second research thrust will be an investigation of the transport and magnetic properties of thin films of ferromagnetic (Ga,Mn)As and MnAs. The basic physics of these materials (which are semiconducting and metallic, respectively) will be probed through magnetic and magnetotransport studies of the pure materials and heterostructures incorporating these ferromagnets with other magnetic and non-magnetic materials. The educational component of the project will involve the dissertation work of at least one graduate student and the active participation of undergraduates in the laboratory. These students will acquire knowledge and skills that will be use in future careers whether in academia, industrial, or government laboratories. %%%This individual investigator project centers on two different research thrusts related to the properties of unusual magnetic materials which are ferromagnetic, i.e. displaying a macroscopic magnetic moment. The specific materials studied are of particular interest because their magnetism is strongly connected to their electronic properties, and advances in the fundamental understanding of this coupling could potentially contribute to "spintronic" technological applications which exploit a combination of magnetic and electronic properties. The first research thrust will be an investigation of phenomena related to the coexistence of two different types of magnetic and electronic phases within a class of compounds known as the "colossal magnetoresistance" perovskite manganites. The second research thrust will be an investigation of the transport and magnetic properties of thin films of ferromagnetic (Ga,Mn)As and MnAs which both can be grown epitaxially on the commonly used semiconductor GaAs and thus may have more immediate technological importance. The educational component of the proposed research will involve the dissertation work of at least one graduate student and the active participation of undergraduates in the laboratory. The training that these students obtain will be valuable for future careers in industry, government, or academia.***