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We prepared poly(vinylidene fluoride) (PVDF) and aluminum composite dense films using a tape caster and investigated the microstructural, thermal, and electrical properties and the combustion behavior of the films as a function of nano-aluminum (nAl) solids loading (5–30 wt. %). We found that the addition of nAl facilitates the formation of piezoelectric β and γ phases of PVDF as determined by x-ray diffraction and Fourier transform infrared spectroscopy. At higher nAl solid loadings, the lower onset temperature of the pre-ignition and decomposition reactions have been observed. Moreover, the intentionally incorporated porosity into the films slightly affected the thermal decomposition behavior. While the dielectric constant of the films increases with higher nAl content, the dielectric breakdown strength of the films decreases significantly. The critical active nAl content for the films to exhibit self-propagated reaction was determined to be between 10 and 15 wt. %. Thermochemical calculations using the NASA CEA code showed the maximum flame temperature of 1750 °C near the stoichiometric ratio (∼20 wt. %). The burning rate of the films is enhanced drastically at ambient conditions with further addition of nAl. However, the films with active nAl content over 20 wt. % showed lower flame temperatures, which is due to the reduction of hydrofluoric acid gas generation and the incomplete combustion of Al to form aluminum monofluoride (AlF), instead of aluminum fluoride (AlF3) gas. The fabrication of energetic thin films with tunable properties could enable their use in multifunctional energetic material systems. [ABSTRACT FROM AUTHOR]

Flash sintering has recently been used to sinter various bulk ceramics under reduced sintering temperatures and sintering time by applying an electric field across the sample. In this work, we have demonstrated field‐assisted heating of 10 mol% Gd‐doped CeO2 thin films deposited by pulsed laser deposition. Microstructure analysis revealed the elongated grains aligned in the out‐of‐plane direction which is perpendicular to the direction of electric field. The overall microstructure of the flash‐heated thin film also contained a matrix of porous and clustered regions, which are distributed throughout the thin film from the anode to cathode electrode regions. The flash‐heated thin film showed significantly different conductivity and optical permittivity compared to the as‐grown thin films. This demonstration suggests a feasible approach for post‐deposition synthesis of thin films using field‐assisted heating toward novel morphologies and properties. [ABSTRACT FROM AUTHOR]

Plasmonic oxide‐metal hybrid nanostructures exhibit unprecedented optical properties because of the nanoscale interactions between the oxide and metal components. Precise control of the geometry and arrangement of optical building blocks is key to tailoring system properties toward various nanophotonic applications. Herein, self‐assembled BaTiO3‐Au vertically aligned nanocomposite thin films with a series of thicknesses are fabricated using a one‐step pulsed laser deposition technique. By reducing the film thickness, the geometry of Au phase is effectively tailored from nanopillars to nanodisks, with the aspect ratio (height/width) varied from ≈4.0 to ≈1.0. The experimental optical spectra and numerical simulation results demonstrate that localized surface plasmon resonance and hyperbolic dispersion wavelength can be effectively tuned in the visible to near‐infrared regime by varying the film thickness due to the change of Au aspect ratio and free electron density. This study demonstrates a feasible approach in tuning the optical responses in hybrid oxide‐metal nanostructures, and opens up enormous possibilities in design and fabrication of novel optical components toward all optical integrated devices. [ABSTRACT FROM AUTHOR]

Metallic nanostructures within ceramic matrices provide a unique platform for integrating magnetic, optical, and electrical properties for device applications. Currently, hurdles still exist for the integration of metallic nanostructures within conventional devices, including the incompatible growth conditions between metals and ceramics and control of the overall physical properties. In this study, we demonstrate the tunability of a one-step growth method to fabricate magnetic and metallic nanostructures embedded within an oxide matrix, La0.5Sr0.5FeO3:Fe, from a composite target using pulsed laser deposition. The metal-ceramic nanocomposite films demonstrate tunable nanostructures and anisotropic magnetic response by varying deposition energy, presenting a mechanism for tuning the physical properties of vertically aligned ferromagnetic metallic nanopillars in an oxide matrix. This study also opens avenues towards the integration of nanoscale, vertical, metallic ferromagnetic contacts for anisotropic magnetic tunneling junctions which may not be easily realized by single-phase thin films. [ABSTRACT FROM AUTHOR]