Studies of Unusual Ferromagnetic Materials

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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.***