On Friday, February 20, 2015, Christina Rost of North Carolina State University Department of Materials Science and Engineering will present a seminar, “Entropically-Stabilized Oxides: Exploring a Novel Class of Multi-component Materials” at 2:30 p.m. in Weyandt Hall, room 331.
Rost is a 2012 graduate of the Department of Physics at Indiana University of Pennsylvania.
demonstrate a novel class of entropy stabilized oxides, characterized by
configurational disorder of the cation species in an oxygen sub-lattice and
exhibiting an unusual degree of structural perfection. Currently, we have
demonstrated this phase phenomenon with several different compositions. The
simplest composition is of rocksalt structure, containing equal amounts of Mg,
Co, Cu, Ni and Zn. More complex structures include spinel, and contain
Mg-Ti-Fe-Cu-Zn and Ni-Ti-Ga-Cu-Zn, among others. Bulk ceramics are synthesized
through solid state sintering above 875°C in air, while thin films are grown
via pulsed laser deposition with a controllable variability between
polycrystalline and epitaxial structures-single crystal, heteroepitaxial layers
are grown on (100) MgO substrates.
In this talk, fundamental questions are
addressed. We show the entropic dependence of our solid solutions by
examining the phase transformation temperature as a function of stoichiometry.
Energy dispersive spectroscopy and x-ray absorption fine structure reveal the
degree of localized disorder within the lattice. Collectively, these new
materials display genuine entropic stabilization and promote new potentials for
complex oxide systems.
All are welcome to attend. Light refreshments will be served.