Rhines Hall Room 125
Gainesville, FL 32611
Join MSE for light refreshments and a discussion on ion-beam modification of ceramics lead by Dr. Weber of the University of Tennessee.
While ion-beam modification of ceramics often refers to the effects of atomic-level elastic collisions processes, interactions of energetic ions with solids results in both inelastic energy loss to electrons and elastic energy loss to atomic nuclei. The coupled effects of these energy loss pathways on defect production, nanostructure evolution and phase transformation in ceramics are complex and not well understood. Using experimental and computational approaches, we have investigated the separate and combined effects of nuclear and electronic energy loss on the modification of ceramics to ion irradiation over a range of energies. Experimentally, ion mass and energy are used to control the amount of energy deposition and the ratio of electronic to nuclear energy loss. Large scale molecular dynamics simulations, which include atomic collision processes and inelastic thermal spikes, are used to model these effects. We have demonstrated: 1) additive effects of nuclear and electronic energy loss on damage production; 2) competitive effects via ionization-induced dynamic recovery; and 3) synergistic effects between pre-existing defects and electronic energy loss on damage production. This diverse range of coupled effects provides new paradigms in ion-beam modification that include the role of electronic energy loss in controlling defects and the formation of functional nanostructures in ceramics. This work advances the understanding on the role of defects in electronic energy dissipation and electron-phonon coupling, and the knowledge gained provides insights for creating novel interfaces and nanostructures with controlled morphologies, multiple phases and local strain, which can be employed to engineer functionalized thin film structures with tunable electronic, ionic, magnetic and optical properties on the nanoscale. These results also have significant implications for the response of materials to extreme radiation environments, dynamics of ion-irradiation effects, and modification of materials using ion beams.
This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division.