Synthesis, structural, dielectric and domain properties of Al-doped KNbO3 single crystal
Single-crystal samples of Al-doped potassium niobate (KNbO3) [KN] were synthesized by a high-temperature flux technique. X-ray diffraction analysis of the crystal suggests that a single phase with an orthorhombic structure was formed. The dielectric studies of the KN single crystal as a function of temperature (from 30 to 500 °C) show that the compounds underwent a phase transition, which was confirmed by thermal analysis of the DTA curve. The measured loss tangent of the crystal, which is in good agreement with the dielectric studies. The ferroelectric property of the crystal was confirmed by studying the hysteresis loop. In this study, several parameters, like the coercive field and spontaneous polarization, were measured and calculated. The domain study was carried out using a trinocular microscope, which reported the formation of the 60° domain line and dislocation etch pits. The effects of the electric field on the domain of the Al-doped KN single crystal were discussed.