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(Pb1−xBax)ZrO3 (x = 0, 0.025, 0.05, 0.075, 0.1) ceramics were synthesized by a traditional solid‐state reaction method, and the pure phase was obtained of all sintered samples. For all compositions, substitution of Pb2+ by Ba2+ reduced the phase transition temperature of antiferroelectric to ferroelectric and Curie temperature. Polarization–electric field hysteresis loops were conducted and typical ferroelectric hysteresis loops were observed in higher temperature range. Impedance and dielectric measurements were studied on the high temperature relaxation. Relaxation behavior could be suppressed after annealing treatment in oxygen atmosphere. Value of activation energy calculated from impedance was lower than that calculated from conduction measurements. It was concluded that short‐range hopping of oxygen vacancy contributes to the dielectric relaxation and long‐distance movement of doubly ionized oxygen vacancies contributes to the conduction.

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The unique properties and great variety of relaxer ferroelectrics make them highly attractive in energy-storage and solid-state refrigeration technologies. In this work, lanthanum modified lead titanate ceramics are prepared and studied. The giant electrocaloric effect in lanthanum modified lead titanate ceramics is revealed for the first time. Large refrigeration efficiency (27.4) and high adiabatic temperature change (1.67 K) are achieved by indirect analysis. Direct measurements of electrocaloric effect show that reversible adiabatic temperature change is also about 1.67 K, which exceeds many electrocaloric effect values in current direct measured electrocaloric studies. Both theoretical calculated and direct measured electrocaloric effects are in good agreements in high temperatures. Temperature and electric field related energy storage properties are also analyzed, maximum energy-storage density and energy-storage efficiency are about 0.31 J/cm3 and 91.2%, respectively.

(1−x)PbZrO3–xSrTiO3 (x: 10, 20, and 30 mol %) ceramics were prepared by a conventional mixed‐oxide solid‐state reaction method. The relaxer behaviors of the PbZrO3–SrTiO3 ceramics were examined in the temperature range of 120–523 K. A broad dielectric maximum that shifted to higher temperature with increasing frequency signified the relaxer‐type behaviors of these ceramics. The value of the relaxation parameter of γ=1.73, estimated from the linear fit of the modified Curie–Weiss law, indicated the relaxer nature. High‐temperature dielectric relaxation phenomena were found in the temperature region of 600‐850 K. The activation energy, calculated from impedance measurements of samples, suggested that the dielectric relaxation was a result of oxygen vacancies generated during the sintering process. The energy‐storage density calculated from hysteresis loops reached about 0.46 J cm−3 for the PSZT30 ceramic at room temperature.