Structural, dielectric, ferroelectric and piezoelectric properties of La and Fe substituted barium titanate ceramics

The effect of simultaneous substitution of La3+ and Fe3+ ions on structural, dielectric, ferroelectric and piezoelectric properties of BaTiO3 was studied. Polycrystalline ceramic samples with composition Ba1-xLaxTi1-xFexO3 with x = 0, 0.005, 0.015 and 0.020 were prepared by the solid-state route and sintered at 1325°C. X-ray diffraction (XRD) analysis confirmed the single phase with tetragonal perovskite structure in all the prepared ceramics. Dielectric constant 'ϵ' and tangent loss 'tanδ' was measured as a function of temperature (25–200°C). The value of ϵ increases with an increase in La and Fe contents. A very small value of tanδ (<4%) was observed. The temperature coefficient of capacitance 'Tcc' was found to be around 10% for all the samples. PE hysteresis loops were recorded at room temperature for all samples. The maximum value of ϵ and piezoelectric coefficient 'd33' was found to be 3735 (at 30°C, 100 kHz) and 140pC/N, respectively for x = 0.020.