*** NON-TECHNICAL ABSTRACT *** Magnetic semiconductors (MSs) continue to be the subject of vigorous research because of their potential application in "spintronics", a novel electronics that may have a great impact on future communication and computer technologies. Naturally occurring MSs are not useful for practical spintronics since they retain their magnetism only at very low temperatures. Therefore, substantial efforts are currently focused on creating new man-made MSs of suitable properties. Several such systems have recently been synthesized, and good understanding of their magnetism is a task of considerable importance. Neutron scattering is a powerful tool for investigating magnetic solids. The objective of this project is to exploit the unique capabilities of neutron scattering techniques for investigating a range of effects of current interest in these novel MSs. Inelastic neutron scattering will be used for obtaining a clear microscopic-level insight into interactions between magnetic atoms in these materials. Some new MSs alloys can be prepared only in the form of ultra-thin films. The technique of neutron reflectometry, which is particularly well suited for investigating thin film magnetism, will be used for studying such utltra-thin MS layers and multilayers containing other materials sandwiched between MS layers. The project involves collaboration with several research groups from the US and other countries. Two graduate students will take part in the research, and the participation of undergraduate students in the project will be encouraged.
The objective of this project is to exploit the unique capabilities of elastic and inelastic neutron scattering techniques for investigating a range of effects of current interest in recently synthesized novel magnetic semiconductors. These materials now receive strong attention because of their potential application in spin-controlled electronics ("spintronics"). In particular, inelastic scattering will be used for investigating propagating spin waves in Ga1-xMnxAs, an extensively studied "prototypical" spintronics material, as well for characterizing the magnetic excitations of isolated Mn-Mn and Co-Co pairs in diluted alloys of Zn1-xMnxO, Zn1-xCoxO and several other materials derived from II-VI semiconductors at ambient pressure and high pressures up to 8 kbar. The results of such experiments are expected to provide much new microscopic-level information about magnetic exchange interactions in these systems. Another substantial part of the project is neutron reflectometry studies of thin film and superlattice structures based on Ga1-xMnxAs and Ge1-x-y MnxCoy. The measurements will be focused on investigating interlayer coupling effects and magnetic domains in such epitaxial systems. The project involves collaboration with several partners from the US and other countries. Two graduate students will participate in the research. Also, participation of undergraduate students will be encouraged and attractive opportunities will be offered to those aspiring young scientists.
