| Abstract Scope |
Oxides ceramics comprise an important class of dielectric and electronic materials, where electrical properties are determined not only by the material’s intrinsic band structure but also but its point-defect chemistry. In polycrystalline materials, the macroscopic conductivity may be significantly affected by grain boundaries, where gradients in defect concentrations lead to gradients in the local potential and carrier concentrations. Consequently, the electrical conductivity of grain boundaries can differ by several orders of magnitude with respect to that of the bulk. This talk will discuss experimental approaches to measuring grain boundary electrical potentials and their contribution to the macroscopic conductivity and degradation behavior of polycrystalline electronic oxides, with focus on dielectric materials for capacitor applications. The experimental approach employs complementary impedance spectroscopy and scanning transmission electron microscopy to develop a holistic understanding of the local grain boundary chemistry and potential profiles. This research was funded by AFOSR under grant FA9550-19-1-0222. |