Dielectric and Piezoelectric Properties of Mn-Modified Bi₄CaTi₄O₁₅Based Ceramics

Abstract

Solid solution ceramics of the Bi4SrxMnyCa1-(x+y)Ti4O15 system were synthesized by the conventional ceramic process. Measurements of dielectric, electromechanical and piezoelectric properties were conducted as a function of both composition and temperature. As a result, it was found that piezoelectric properties are greatly improved as the appropriate amount of Mn ion is introduced into the Ca ion-site. Maximum values obtained are as follows: electromechanical coupling factor kP=0.064, piezoelectric constant d33=21 pC/N for the composition with x=0.5 and y=0.1 (Bi4Sr0.5Mn0.1Ca0.4Ti4O15), and the mechanical quality factor Qm=3250 for the composition with x=0.5 and y=0.05 (Bi4Sr0.5Mn0.05Ca0.45Ti4O15). Piezoelectric constant d33 was found to take nearly the same value of 20 pC/N over the range of x=0.4 to 0.9 for the fixed y of 0.1.