Temperature Dependent Conduction Studies of Multilayer Material Systems

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Conduction in multilayer materials is currently of great interest, but is neither well understood nor has it been exhaustively investigated. Measurement of conduction processes is fundamental in material science, and because it is relatively straightforward it is ideal for upper-level students at undergraduate institutions. In this project, a low-temperature cryostat is integrated into an existing resistivity and Hall effect apparatus and used to study the temperature dependence of the electronic transport properties of multilayer materials. The apparatus has been under development and is now used in a junior- level advanced laboratory course to study metal and semiconductor systems. The cryostat greatly increases the experimental capabilities in the junior-level laboratory course and in independent study and senior-level thesis projects. New projects focus on the temperature, magnetic field, current direction, and layer spacing dependencies of the magnetoresistance and Hall voltage in multilayer systems. Low- temperature capabilities allow the transport properties to be characterized over a temperature range broad enough to study the nature of the electronic scattering mechanisms. Initial systems of study are C/Ge and W/Si multilayers, with layer thicknesses ranging from 5 to 50 Angstroms. Fabrication and structural studies of these multilayers are performed in collaboration with another research group. This project should increase the presence of material science education and research at undergraduate institutions.