Structural, dielectric and electrical characteristics of yttrium modified 0.7BiFeO3-0.3PbTiO3

Some yttrium modified BiFeO3-PbTiO3 (BYFO-PT) compounds have been fabricated using a standard ceramic technology (solid-state route). The structural analysis from X-ray diffraction (XRD) data ensures the formation of the rhombohedral phase of the compounds. The prepared materials have major bismuth ferrite (70%) and lead titanate (30%) with few impurity phases. The materials are found to have a high dielectric constant and low tangent loss. The relaxation mechanism is identified from the peaks appearing in impedance and modulus curves. The materials show a negative temperature coefficient of resistance (NTCR) semiconductor type behavior in the temperature range of 250 degrees C-400 degrees C. In addition, grain and grain boundary effects are observed through the Nyquist plots. The activation energy (E-a) of the compounds is calculated from the slope of inverse temperature versus AC conductivity at the high-temperature range. The ferroelectric nature of the compounds is confirmed by electric field dependent polarization (PE-hysteresis) loops.