EFFECT OF ALKALINE EARTH SUBSTITUTION ON ELECTRICAL PROPERTIES OF SrBi₄Ti₄O₁₅ CERAMICS

ABSTRACT

Ferroelectric Sr_1–xCa_xBi₄Ti₄O₁₅ (SCBT-x x = 0.00, 0.20, 0.40, 0.50, 0.70, 0.90 and 1.00) ceramic samples were prepared using the conventional solid-state reaction. The Curie temperature (T_c) increases with Ca doping. The temperature dependence of dielectric loss (tan δ) shows two dielectric anomalies at x = 0.20 while only one dielectric loss peak is found in other cases. The remnant polarization (2P_r) and coercive field (E_c) of nondoped SrBi₄Ti₄O₁₅ are about 15.7 μC/cm² and 107 kV/cm, respectively. Small amount of Ca doping increases the 2P_r, the 2P_r reaches a maximum value of 17.6 μC/cm² and E_c is increased to 113 kV/cm when x = 0.20. The piezoelectric coefficient (d₃₃) shows the maximum values of 9.0 pC/N at x = 0 and decreases almost linearly with the increase in x.

Keywords:

• Ceramic
• Ferroelectricity
• Dielectricity
• Piezoelectric coefficient

ACKNOWLEDGMENTS

The authors acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 10274066) and the Jiangsu Provincial Natural Science Foundation (Grant No. BK2005052).