Dielectric and Ferroelectric Studies on Sol-Gel Derived Calcium Modified Lead Zirconate Titanate Ceramics

Abstract

Bulk samples of Pb_(1-x)Ca_xZr_0.52Ti_0.48O₃ (x = 0,0.02,0.04,0.06,0.08,0.1) have been synthesized by sol-gel process using lead acetate trihydrate, calcium acetate hydrate, zirconium propoxide and titanium propoxide as the starting materials. The dependence of ferroelectric phase transition temperature T_c as a function of calcium substitution has been investigated. A linear decrease of T_c is observed with increasing calcium concentration. The variation of room temperature dielectric constant and that of maximum value of dielectric constant corresponding to the phase transition temperature are explained by the microstructural studies. XRD patterns of the samples show that all the compositions sintered at 1200°C are having single phase with perovskite structure. P-E hysteresis loop measurements showed that calcium modified PZT ceramics have higher P_r values than that of pure PZT composition prepared by sol-gel method. The composition with 4 mol% calcium has the highest value of P_r, 25.2 μC/cm² and lowest E_c, 9.6 kV/cm.

Keywords:

• PZT
• ferroelectric
• pyroelectric
• dielectric

Acknowledgments

One of the authors (Anupama Sachdeva) is grateful to the Principal, Keshav Mahavidyalaya, University of Delhi, for granting study leave for undertaking this work. Thanks are also due to O. P.Thakur and N. C. Mehra for their support in the experimental work.