Fig. 8(e) shows the P-E hysteresis

Fig. 8(e) shows the P-E hysteresis loops of the KNN ceramics sintered at 1115°C by CSAS and CS methods. Both of the P-E hysteresis loops are well saturated, which confirms excellent ferroelectric properties. The remnant polarization Pr and coercive field Ec for CSAS and CS produced KNN ceramics are about 17.3C/cm2, 8.3kV/cm2 and 12.2C/cm2, 13.5kV/cm, respectively. As known, the evaporation of A-site cations would increase the oxygen vacancy concentration, which may enhance the pinning effects and decrease domain wall mobility, and correspondingly increase the coercive field. In this sense, higher remnant polarization Pr and lower coercive field Ec for CSAS samples might relate to fewer volatilization contents of A-site cations such as Na+ and K+.