Restraining the Laws of Nature with a Layer of Atoms

Dr. R. J. Smith, Physics Department, Montana State University

The technique of MeV ion backscattering and channeling has been used to study the interface structure and stoichiometry for thin transition metal films deposited on Al single crystal surfaces.  Analysis of the backscattering data is based on the concepts of shadowing and the well-known theory of Rutherford scattering.  First, we consider the growth of ordered Ti films on Al single crystal surfaces, and ordered alloy formation at the Ag-Al interface.  We then discuss measurements for alloy formation at the Ni-Al(110) interface, along with results from Monte Carlo simulations of the interface evolution.  Finally, an approach is described to stabilize metal-metal interfaces using an extremely thin metallic interlayer. Specifically, a single layer of Ti atoms deposited at the Fe-Al interface, a system well known for considerable intermixing at room temperature, is shown to prevent interdiffusion, resulting in the ordered growth of Fe films on the Al(100) surface.  The resulting structure is stable up to about 200 oC.  

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