This award from the Condensed Matter Physics Program of the Division of Materials Research supports the University of Tennessee at Knoxville with a project focused on the design, discovery, and characterization of new materials for spintronics. Spintronics is the field that makes use of the electric charge and the spin (magnetic moment of the electron)of the electron to create new energy efficient device functionalities. Spintronics is a fast-developing field and it is expected to be further transformed by exploiting the properties of a class of material known as chalcogenides. Atomically thin layers of chalcogenides are true semiconductors and can lead to next generation of high performance electronic devices such as field-effect and photo- transistors. The fusion of spintronics with two dimensional chalcogenide semiconductors is expected to lead to revolutionary advances in nanoelectronics. As synthesis and crystal growth are excellent tools to reach undergraduate students, the research program is designed to actively involve undergraduates and kindle their interest in science. The hands-on experience of the students is complemented by a new course entitled "Nanomagnetism and Spintronics" to be taught at the advanced undergraduate level. In addition, the program supports the P.I.'s outreach activities, allowing the development of new demonstrations for middle school students based on superconductivity and magnetism.
The objective of this project is to design, discover, and characterize new spintronic materials based on the remarkable electronic and magnetic properties of layered chalcogenides. The project is focused on two classes of spintronic materials. One class involves the formation of a chiral soliton lattice (CSL) in layered, metallic helical magnets. The CSL is a lattice of solitons (domain wall boundaries) separated by ferromagnetic regions. The CSL periodicity is tunable using modest applied fields and this effect is predicted to lead to unique spintronic functionalities, such as spin current induction, soliton transport, and current-driven collective transport. The second class of materials involves stoichiometric quasi-2D magnetic semiconductors with high mobility. These materials order magnetically and potentially can be used in single-layer devices that may be useful as spin injectors, sensors, or transducers. One of the goals of this project is to elucidate design principles for CSL materials and quasi-2D magnetic semiconductors. Single crystals of targeted materials are grown using both flux and vapor transport techniques. The anisotropic properties of the materials are characterized using SQUID magnetometry and electrical transport. Small angle neutron diffraction is performed to characterize the helical order of the CSL materials and probe their response to magnetic fields. Single-layer field-effect devices made from semiconducting 2D ferromagnets are fabricated and their electrical properties characterized. As synthesis and crystal growth are excellent tools to reach undergraduate students, the research program is designed to actively involve undergraduates and kindle their interest in science. The hands-on experience of the students is complemented by a new course entitled "Nanomagnetism and Spintronics" to be taught at the advanced undergraduate level. In addition, the program supports the P.I.'s outreach activities, allowing the development of new demonstrations for middle school students based on superconductivity and magnetism.
