Titanium Carbide Obtained by Magnetron Sputtering of Graphite on Heated Titanium Substrate

Titanium carbide was synthetized by sputtering graphite target on heated titanium substrate by magnetron sputtering process. The obtained samples were characterized by X-ray diffraction (XRD) analysis and Raman spectroscopy, the elemental analysis was made by Energy-dispersive X-ray spectroscopy (EDX). Titanium carbide (TiC) structure was obtained by deposition of sputtered carbon atoms and clusters to the resistively heated titanium substrate surface with temperatures 700 °C, 800 °C, 900 °C and 1000 °C. The XRD analysis showed that the formation of TiC structure is take place when the substrate is heated to 1000 °C. The Raman spectroscopy showed that when the incident power of laser is 100 % (35 mW) the structure is unstable in samples with the substrate temperatures 700 °C, 800 °C and 900 °C and the most stable titanium carbide structure is created when the substrate temperature is 1000 °C

Electrical Conductivity and Dielectric Properties of Bi4_{4}Ti3_{3}O12_{12}

The present paper deals with the investigation of electrical and dielectric properties of structures based on Bi$_{4}$Ti$_{3}$O$_{12}$ films. It has been found that the nonlinearity of the $I - U$ characteristics in Me-Bi$_{4}$Ti$_{3}$O$_{12}$-Me structures is attributed to intercrystalline potential barriers. The height of the intercrystalline barrier ($\Phi_{0}=0.12$ eV) and the mean size of crystallise ($L=0.3~\mu$m) have been determined. At rather low temperatures, the hopping conductivity with a mean length of hopping, $\sim 2.6 \times 10^{19}$ cm$^{-3}$ eV$^{-1}$, is shown to be a dominant process at the charge transfer. It has been found that the electrical conductivity ($\sigma$) in the direction parallel to the $C$-axis (“sandwich” configuration) shows an anomaly in the phase transition region ($\sim 950$ K), while in the direction perpendicular to the $C$-axis, a simple bending of $\sigma$ vs. $T$ is observed. The latter is explained by the change of spontaneous polarization in Bi$_{4}$Ti$_{3}$O$_{12}$ films. The temperature dependence of the dielectric constant and the dielectric loss tangent have the maxima in the range of the phase transition temperature. The dielectric constant values are $\sim 650 \sim 120$ for the structures of “sandwich” and planar configurations, respectively. This fact indicates the presence of a polarization component in the given direction. The diffusion of the phase transition is explained by the imperfection of the film structure