To induce fine engineered domain configurations into potassium niobate (KNbO3) single crystals, two kinds
of methods were performed, i.e., (1) high DC electric field exposure along the opposite direction of
polarization of KNbO3 single-domain crystals at room temperature, and (2) introduction of randomly
oriented fine domain configuration by heat treatment at 700 °C and then high DC electric field exposure
along [001]c direction of KNbO3 multidomain crystals at room temperature. When the method (1) was
performed, finally, the poled KNbO3 crystals became to single-domain state again through the formation of
multidomain state. On the other hand, the KNbO3 multidomain crystals were obtained by using the method
(2), and an enhancement of piezoelectric-related properties was observed.
