Effect of La and Sc co-doping on dielectric and ferroelectric properties of PZT for energy storage capacitors

Abstract

In this work, we report a systematic study of complex La3+ and Sc3+ doped lead zirconate titanate ceramics with the stoichiometric formula (PbZr0.53Ti0.47)0.90 (LaxSc1−x)0.10O3−δ for x = 0.2, 0.4, 0.6, and 0.8 denoted as PLZTS2, PLZTS4, PLZTS6, and PLZTS8, respectively (abbreviated as PLZTS10x), synthesized using the solid-state reaction method. We carried out dielectric measurements on Ag/PLZTS10x/Ag metal-ferroelectric-metal capacitors as a function of temperature (100-650 K) and frequency (102-106 Hz). Upon increasing La3+ concentration, the dielectric constant was found to be increased up to x = 0.6 and attained the highest value of ∼1800 at room temperature, and consequently, the highest saturation polarization was observed. The relaxor behavior of PLZTS8 can be attributed to the polar nano regions created in the materials. A recoverable energy density of ∼1162 mJ/cm3 with an excellent efficiency of ∼79% was achieved under an applied electric field of 97 kV/cm. The demonstrated high dielectric constant (ɛ′), spontaneous polarization (Ps), and energy density make these bulk materials promising for ferroelectric memory and energy-storage applications.