Structural, dielectric and electrical analysis of Ba_2−xLa_4 + 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 Ba 22x La 4 1 2x/3 Ti 8 O 24 (x 5 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 (e r ), loss tangent (tan d), and AC conductivity (r ac ) 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 5 0.6 showed minimum value of s f. Thus, the prepared samples could be the dielectric materials for the practical applications like resonators, filters, antennas, etc.