Structural, dielectric and electrical analysis of Ba2−xLa4 + 2x/3Ti8O24ceramics system with frequency and temperature

Abstract

In the present investigation, the study of structural, dielectric, and electrical properties of lanthanum doped barium titanate ceramics with structural formula Ba2−xLa4 + 2x/3Ti8O24 (x = 0.0, 0.2, 0.4, 0.6) was reported. The target samples were obtained by mixed oxide route technique. Preliminary X-ray diffraction studies revealed the single phase formation in the orthorhombic crystal structure. The surface morphology of the samples showed that there were well-defined grains of different sizes and shapes that were homogenously distributed on the surface of samples. The approximate grain size was also calculated. The dielectric properties like dielectric constant (er), loss tangent (tan δ), and AC conductivity (σac) and temperature coefficient of resonant frequency were studied in the temperature range of 298—623 K and frequency range of 10 KHz–1 MHz. Dielectric response showed low temperature dispersion in dielectric properties at low frequency. This showed the space charge phenomenon arising due to defects. DC resistivity measured at room temperature for different compositions decreased with increase in substitution. All four samples gave very small value of temperature coefficient of resonant frequency. Sample with x = 0.6 showed minimum value of τf. Thus, the prepared samples could be the dielectric materials for the practical applications like resonators, filters, antennas, etc. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1679–1686, 2016