Electric-field-induced strain in Mn-doped KNbO3 ferroelectric ceramics

Potassium niobate, KNbO3 (KN), ceramics doped with manganese (Mn) were prepared by a modified conventional ceramic fabrication process to characterize their dielectric, ferroelectric and electrostrain properties. In this study, 0.22% of a large electric-field-induced strain was obtained at 80 kV/cm under unipolar driving for 1.2 wt% MnCO3-doped KN ceramics. Basically, it is difficult to obtain dense and nondeliquescent KN ceramics by the conventional method because of potassium ions. The key factor in obtaining dense and nondeliquescent KN ceramics is the calcination process control. Thus, the two-step calcination pattern is proposed for this purpose. Dense, nondeliquescent and high-resistivity Mn-doped KN ceramics were obtained, resulting in a large electric-field-induced strain under a high electric field.