FERROELECTRIC, PIEZOELECTRIC AND DIELECTRIC PROPERTIES OF Nb MODIFIED Bi₄Ti₃O₁₂-SrBi₄Ti₄O₁₅ INTERGROWTH

ABSTRACT

Doping and constructing intergrowth are found to be an effectual approach to modify the electrical properties of bismuth layer-structured ferroelectrics. In this work, ferroelectric, piezoelectric and dielectric properties of Nb-doped Bi₄Ti₃O₁₂-SrBi₄Ti₄O₁₅ (BTN-SBTN-x) intergrowth ceramics were investigated. The ferroelectric property of Bi₄Ti₃O₁₂-SrBi₄Ti₄O₁₅ was improved by niobium doping. The remanent polarization (2P _r ) increases at first, then decreases with the increase of niobium content, while the coercive field changes little with Nb-doping. As niobium content is 0.06, the 2P _r maximizes at a value of 34.9 μC/cm², which is increased by about 75% in comparison with that of Bi₄Ti₃O₁₂-SrBi₄Ti₄O₁₅ (2P _r = 20.0 μC/cm²). The Curie temperature of the samples varies hardly upon Nb-doping, which indicates that the good thermal stability of Bi₄Ti₃O₁₂-SrBi₄Ti₄O₁₅ is not deteriorated after Nb addition. Piezoelectric coefficient d₃₃ was increased from 9.3 pC·N⁻¹ to 18.6 pC·N⁻¹ due to the enlargement of 2P _r .

Keywords:

• doping
• remanent polarization
• Curie temperature
• piezoelectric coefficient

ACKNOWLEDGMENTS

The authors acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 10274066) and the Natural Science Foundation of Education Bureau of Jiangsu Province, China (Grant No. GK2005052).