Study of Ferroelectric Transitions of Solid-Solution Single Crystals of KNb O 3 -KTa O 3

摘要: Methods of preparation and results measurements the dielectric constant solid-solution single crystals KNb${\mathrm{O}}_{3}$ KTa${\mathrm{O}}_{3}$ are presented. Data given for composition range 0-80 mole percent in temperature interval -180\ifmmode^\circ\else\textdegree\fi{}C to 450\ifmmode^\circ\else\textdegree\fi{}C. It is found that all studied show Curie-law behavior paraelectric state. The data indicate ferroelectric transition, which first order pure KNb${\mathrm{O}}_{3}$, becomes second at a concentration approximately 55 KTa${\mathrm{O}}_{3}$. Analysis terms Slater's model ferroelectricity perovskite lattice leads conclusion dependence Lorentz correction on volume plays major role determining behavior. Ionic polarizabilities their also discussed.