Piezoelectric and pyroelectric properties of Cu-doped CaBi4Ti4O15 lead-free ferroelectric ceramics

Dense Cu-doped CaBi4Ti4O15 ferroelectric ceramics have been fabricated by a conventional ceramic technique. After doping by Cu, the ceramics become denser, and their electrical, piezoelectric and pyroelectric properties are improved. At the optimum doping level of 0.5 mol%, the ceramic exhibits a high density (6940 kg m(-3)), a low dielectric constant (145), a low dielectric loss (0.12%), a high resistivity (2.5 x 10(13) Omega cm), a large piezoelectric coefficient (12.4 pC N-1) and a large pyroelectric coefficient (86 mu CK-1 m(-2)). Unlike the piezoelectric properties, the pyroelectric properties, in particular those relating to the pyroelectric detection, of the ceramics are good and comparable to those of the lead-based ferroelectric ceramics. For the ceramic doped with 0.5 mol% Cu, the voltage and detectivity figures of merit for pyroelectric detection have large values of 2.6 x 10(-2) m(2) C-1 and 2.7 x 10(-5) Pa-1/2, respectively, indicating that it is a promising candidate for pyroelectric applications.