Structural, dielectric and electrical properties of Al +3-modified PLZT ceramics

Abstract

Polycrystalline samples of [Pb 0.92(La 1− z Al z ) 0.08][Zr 0.60Ti 0.40] 0.98O 3 ( z=0.0, 0.3, 0.6, 0.9, 1.0) were prepared by a high-temperature solid-state reaction technique. Preliminary X-ray study at room temperature shows the formation of single-phase compounds in the tetragonal crystal system. Scanning electron microscopy (SEM) study was employed to observe the microstructure and distributions of grains of the sintered ceramics. Detailed studies of dielectric constant ( ϵ) and tangent loss (tan δ) of the compounds as a function of frequency (100 Hz–1 MHz) at different temperature (30–400 °C) show that the compounds have a diffuse ferroelectric phase transition. As we increase z, transition temperature shifts towards higher temperature side. The dc conductivity of the material (as evaluated from the impedance analysis) has been observed to be ∼10 −8 S cm −1 at room temperature (RT) and ∼10 −4 S cm −1 at 550 °C which has indicated a typical semiconductor like behavior with negative temperature coefficient of resistance (NTCR).