Impedance Spectroscopy of Dielectric BaTi5O11 Film Prepared by Laser Chemical Vapor Deposition Method.

BaTiO film was prepared on Pt/Ti/SiO/Si substrate by the laser chemical vapor deposition method. A single-phase BaTiO film with $$ (\overline{3} 22)/(\overline{2} 23) $$ preferred orientation and columnar cross-section was obtained at high deposition rate (154.8 μm h). The dielectric constant ( ε) of the BaTiO film was 21, measured at 300 K and 1 MHz. The electrical properties of the BaTiO film were investigated by ac impedance spectroscopy from 300 K to 1073 K at 10 Hz to 10 Hz. Plots of the real and imaginary parts of the impedance ( Z′ and Z″) and electrical modulus ( M′ and M″) in the above frequency and temperature range suggested the presence of two relaxation regimes, which were attributed to grain and grain boundary responses. The ac conductivity plots as a function of frequency showed three types of conduction process at elevated temperature. The frequency-independent plateau at low frequency was due to dc conductivity. The mid-frequency conductivity was due to grain boundaries, while the high-frequency conductivity was due to grains. [ABSTRACT FROM AUTHOR]