Domain structures and piezoelectric properties of low-temperature sintered (Ba0.95Ca0.05)(Ti0.94Sn0.06)O3 ceramics with CuO additive

(Ba 0.95 Ca 0.05 )(Ti 0.94 Sn 0.06 )O 3 - x mol% CuO ceramics were fabricated to investigate their domain structures and piezoelectric properties. The CuO additive significantly improved the densification behavior of the ceramics, resulting in a reduced sintering temperature by ~150 °C. Increasing x shifted the orthorhombic-tetragonal phase transition towards lower temperatures, and caused the specific ratio of tetragonal to orthorhombic phase to increase at room temperature. The herringbone domain patterns became much simpler and their number substantially decreased. The watermarks and parallel strips are the dominant domain configuration in ceramics with x =0.50 which show the optimum piezoelectric properties: d 33 ~516 pC/N, d 33 * ~996 pC/N, k p ~0.42, and Q m ~352. The underlying physical mechanisms for the enhanced piezoelectricity in the CuO-doped ceramics were discussed.