Electrical properties of mn-modified CaBi4Ti4O15 piezoelectrics for high temperature application

Mn-modified CaBi4Ti4O15 (CBT+x mol% MnCO3) layer-structured piezoelectric ceramics were prepared by the solid state reaction technology. All samples have the same Curie temperature of 780 degrees C, but the dielectric loss at high temperature is remarkably lowered by Mn addition. With increasing content of Mn, the remnant polarization is slightly decreased; the dielectric constant at room temperature decreases from 173 to 162; and the mechanical quality factor increases from 2700 to 4400. The piezoelectric constant d(33) is enhanced from 7 to 14.5. The resistivity of 1.0mol% Mn modified sample is found to be 10(8)Omega center dot cm at 500 degrees C, 50 times higher than that of pure CBT. The Arrehenius plot of Mn-modified CBT is fitted by 3 straight lines, while that of pure CBT is fitted by 2 straight lines. The results suggest that the Mn modified CBT is a potential material for high temperature sensing application.