Preparation, Structure, and Dielectric and Nonlinear Optical Properties of (K0.5Na0.5)NbO3-BaZrO3 Ceramics

Single-phase (1 - x)(K0.5Na0.5)NbO3 & sdot;xBaZrO3 (x = 0-0.06) ceramics with new compositions, including those modified with SiO2 and ZnO oxide additions, have been prepared and their crystal structure, microstructure, and dielectric and nonlinear optical properties have been studied. A phase with the perovskite structure and an orthorhombic unit cell has been shown to form in all of the synthesized materials. Partial replacement of cations of the basic composition by cations of the combined additive has been demonstrated to cause an increase in unit-cell volume. The ferroelectric phase transitions in the ceramics have been confirmed by dielectric spectroscopy and laser radiation second harmonic generation measurements. Doping with SiO2 and ZnO oxide additions has been shown to lower the temperatures of the transitions from the orthorhombic ferroelectric phase to a tetragonal ferroelectric one and then to a cubic paraelectric phase.