Effects of MnO Additive on Piezoelectric Properties in Modified (Pb, Ca)TiO3 Ferroelectric Ceramics

Effects of MnO additive concentration and poling field dependence on the properties in (Pb0.76Ca0.24) ((Co1/2W1/2)0.04Ti0.96)O3 ceramic material were investigated. A small amount of MnO additive, up to 1.0 mol%, increases electrical resistivity for the ceramic and facilitates the poling procedure. Electromechanical coupling factor thickness mode Kt increases with increasing poling field and exhibits Kt=0.53, while coupling factor planar mode Kp decreases to a negligibly small value of Kp≃0 over 45 kV/cm at 100°C. This phenomenon is probably due to 90° domain rotation of the ceramic caused by strong poling field.