Steve Martin has more than 25 years of experience in the preparation, characterization, and impedance spectroscopy of ion conducting glasses. He has two laboratories for glass synthesis and characterization and has state-of-the-art IR, Raman, and impedance spectrometers and a world glass glove box glass preparation facility that can be used to prepare almost any glass. Martin’s students will prepare and characterize the properties, ionic conductivity, and vibrational spectroscopy of the MGF glasses.
Density, Tgs, and mechanical moduli will be determined using standard methods. The d.c. and a.c. ionic conductivities will be measured using impedance spectroscopy. This system from Novocontrol will be installed in spring 2007 and will be operational at the start of this research project. Ionic conductivities from 100 to 800 K and 1 mHz to 3 GHz will be measured with this system. IR and Raman spectra will be used for short range structural studies and compositional purity analyses. The density data will be used for the modeling (Ilmenau) and diffraction experiments (CMU and Chalmers). The Tgs will be used to determine the safe upper temperature limits for the conductivity and tracer diffusion measurements. The moduli measurements will yield input data for models of the activation energy. The d.c. conductivity will be used to determine the composition dependence and magnitude of the MGFE and the a.c. conductivity will be used by the Munster group to develop models of the ion dynamics. The IR and Raman spectra will be used to help develop models of the structure of the glasses (Ilmenau). This will provide a starting point for more refined models of the structure of these glasses through diffraction (CMU, Chalmers), modeling (Ilmenau), and NMR (Munster) studies. The glass samples will be provided to CMU (XRD), Cornell (tracer diffusion), Munster (NMR), and Chalmers (ND) and in this way all samples will be exactly the same, prepared in exactly the same way with the same composition (and impurities), structure and properties. This will create the most reliable sets of data that can be used in most reliable manner possible to produce the best possible models of the data. ISU is supporting two graduate and two undergraduate students to conduct their research.