Elizabeth Dickey
Professor Elizabeth Dickey and her research group focus efforts on understanding internal interfaces in solid-state materials. Through support from NSF, one area of interest to Professor Dickey is grain boundary segregation in oxide ceramics. Using TiO2 as a model system, Professor Dickey couples analytical transmission electron microscopy (TEM), atomistic modeling (performed by Susan Sinnott at the University of Florida) and thermodynamic modeling to better understand the effect of various acceptor and donor dopants on the properties of grain boundaries. By supplementing TEM with electron energy loss spectroscopy (EELS) and energy dispersive x-ray spectroscopy (EDXS), chemistry and point defect densities at grain boundaries can be elucidated. In collaboration with the Penn State Center for Dielectric Studies (CDS), Professor Dickey is expanding her research on grain boundaries to include the effect of dopants on the dielectric properties of nanometer grain sized BaTiO 3.
Z-Contrast scanning transmission electron micrograph
of a cubic-zirconia grain boundary.
The white dots correspond to Zr atomic columns.
Another research topic for Professor Dickey and her research group is that of ultra high temperature composites through funding from the US Air Force. Directionally solidified oxide and ceramic eutectics, such as Y2AL3O12 and Alumina, are capable of sustaining temperatures in excess of 1400 °C. Using x-ray diffraction (XRD) fitted with a hot stage capable of tri-axial stress measurements up to 900 °C, Professor Dickey hopes to tailor the properties of these composites to reduce the stresses experienced in high temperature, cyclical environments.
Professor Dickey's third research focus is the in the nanoscale arena. Through a MRSEC/MRI seed grant, Professor Dickey is providing structural and chemical analysis using high resolution TEM for new nanomaterials developed by her collaborators Joan Redwing (MatSE) and Nitin Samarth (Physics). In another nanoscale-focused collaboration supported by NSF, this time with Craig Grimes (EE), she is characterizing rare-earth-element doped multi-walled carbon nanotubes. These nanotubes posses interesting optical properties and the focus of this research lies in the understanding and refinement of doping during the growth of the nanotubes.
Housed in the MRI and MRL Buildings, Professor Dickey's primary research tools are analytical instruments: TEM coupled with EELS and EDXS, XRD, atomic force microscopy (AFM) and magnetic force microscopy (MFM). The new JEOL 200 kV field emission scanning transmission electron microscope (FE-STEM) with EELS and EDXS provides atomic scale imaging at a resolution of 1.9 Angstroms. The XRD is uniquely outfitted with a hot stage that allows for measurements at elevated temperatures (up to 900 °C) by fitting a polymer dome over the stage without diminishing the available diffraction space. The AFM/MFM instrument is capable of operating under vacuum or in an inert atmosphere, and at depressed or elevated temperatures.
After receiving her Ph.D. in Materials Science and Engineering from Northwestern, Professor Dickey moved to an Assistant Professorship in 1997 at the University of Kentucky. Professor Dickey moved to Penn State in the summer of 2001.
