Effect of Co/Mg ratio on the phase, microstructure, dielectric and impedance properties of lead zirconate titanate

Polycrystalline PbTi0.5Zr0.3(Co1-x Mg (x) )(0.2)O-3 (x = 0.00, 0.25, 0.45, 0.65, 0.85) ceramics were synthesized using sol-gel route at 1150 A degrees C for 2 h in air. The final ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy and impedance spectroscopy. XRD studies confirmed the tetragonal symmetry (P4mm) of the sintered ceramics. The dielectric constant (epsilon(r)) was found to increase with increasing temperature in the given temperature regime (30-300 A degrees C). Sample with x = 0.25 exhibited high magnitude of epsilon(r) (4261) and dielectric loss (tan delta = 0.05) over a wide range of temperature at 100 kHz. Magnitude of tan delta of the sample with x = 0.65 was recorded to be 0.009 around room temperature at 100 kHz. Resistance of ceramic samples was decreased with an increase in temperature demonstrating a non-Debye type of relaxation process. The AC conductivity of PbTi0.5Zr0.3(Co1-x Mg (x) )(0.2)O-3 samples increased gradually with increasing temperature and frequency.