抄録
The pyroelectric properties of (Pb1-x, Cax) [(Co1/2W1/2)Ti]O3 ceramics have been studied by substituting Ca for Pb and by measuring spontaneous polarization using the Sawyer-Tower method in order to clarify the mechanism responsible for the improvement of pyroelectric property. With an increase in the Ca concentration range of x=0.20-0.30, spontaneous polarization, Ps increases and reaches large values of 40-42μC/cm2 at 100°C, as compared to the 2-3.5μC/cm2 of the representative PbTiO3 ceramics containing small amounts of La and Mn. The Curie temperature decreases according to the Vegard law. The coercive electric field Ec markedly decreases from 28kV/cm at a Ca concentration of x=0.10 to 4kV/cm at a Ca concentration of x=0.40, compared with the 60kV/cm of PbTiO3 ceramics. Increasing spontaneous polarization might be explained in terms of lattice distortion by Ca ions. It is found that a significant improvement of pyroelectric properties is related to an increase in spontaneous polarization Ps and a decrease in the Curie temperature.
