Synthesis and Characterization of Nanocrystalline (Zr₀.₈₄Y₀.₁₆)O₁.₉₂-(Ce₀.₈₅Sm₀.₁₅)O₁.₉₂₅ Heterophase Thin Films

A new type of nanocrystalline samarium-doped-ceria/yttrium-stabilized-zirconia (SDC/YSZ) heterophase thin film electrolytes was synthesized on MgO and Si substrates by spin coating and thermal treatment of SDC-nanoparticle-incorporated polymeric precursors. In the heterophase films, SDC nanoparticles were uniformly dispersed in a nanocrystalline YSZ matrix. The heterophase structure was stable when fired in air at temperatures up to 850 °C. The nanocrystalline heterophase thin films exhibited electrical conductivities significantly higher than that of the phase-pure YSZ and SDC nanocrystalline thin films at reduced temperatures. The effects of SDC grain size and volume fraction on the electrical conductivity of the heterophase films were also studied

Anisotropic Thermal Diffusivity and Conductivity in La-Doped Strontium Niobate Sr2Nb2O7

The thermal diffusivity of the La-doped layered perovskite Sr2Nb2O7 parallel and perpendicular to the perovskite layers is reported from room temperature up to 1000°C. The anisotropy persists through an incommensurate-normal ferroelectric phase transformation at 215°C and up to 1000°C, the maximum temperature of our measurements. The thermal conductivity perpendicular to the perovskite layers, derived from the diffusivity in the same direction, calculated using the density and measured heat capacity, has a constant value of 1.05±0.05 W/mK up to 1000°C. Possible explanations for the low thermal conductivity and anisotropy are described.Engineering and Applied Science