Some Studies on Ferroelectricity in KNO₃ and Related Compounds

抄録

(NH₄)_xK_1−xNO₃ mixed crystals have been found to show ferroelectricity for a wide range of concentration. Dielectric measurements and infrared absorption studies were carried out. The librational behaviors of the NO₃ radical about the 3-fold axis and the axes perpendicular to the 3-fold axis were analysed. The librational frequency and the mean declination angle of the radical were estimated. The Lorentz correction for various rhombohedral angles was calculated, and the ferroelectric effect in the KNO₃ type ferroelectrics was discussed in terms of the local field. The ferroelectric transition has been explained to occur when the rhombohedral angle reaches a particular value.