KNbO3 and LiNbO3 powders and thin films were fabricated through heat-treatment of their peroxide precursors prepared by the reaction of aqueous hydrogen peroxide solution with metal alkoxide. In comparison with the conventional alkoxide solution method, which is not successful for KNbO3, aqueous peroxide solution method is successful for KNbO3 with the advantages such as low weight loss and easy handling in preparing the niobates.
Lead potassium niobate crystals were grown by our pulling down method and tube-seed Czochralski method. Evaporation of lead and potassium was observed. Crystal growth was not so difficult despite the evaporation. Grown crystals were brownish and transparent. Cleavage was observed in the Czochralski grown crystals on the c-plane. After heat treatment, the dielectric constant along the c-axis was about 500–1000. A large dielectric constant above 10000 was observed on the a
b-plane. On the a
b-plane, almost isotropic properties were obtained on the basis of the dielectric constant and the thermal expansion coefficient.
We have demonstrated a synthetic procedure for nano‐sized NaNbO3 powder and its thin films using a carbon‐free precursor prepared by the reaction of H2O2 with sodium and niobium alkoxides. A combination of X‐ray powder diffraction, Raman spectra, and thermal gravity and differential thermal analysis, carbon analysis, fourier transform infrared spectra, transmission electron microscopy, and atomic force microscopy was used to characterize the resulting materials and precursor compounds. Results show that this procedure demonstrates the major advantages of low‐temperature synthesis (∼400°C) and low weight loss during transformation into NaNbO3 because of its carbon‐free nature, which also provides the option of preparing nano‐sized particles and dense, crack‐free NaNbO3 thin films.
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