Structural and Optical Studies on Manganese doped, Modified Sodium Potassium Lithium Niobate Lead-free Piezoelectric Ceramics

摘要

Structural and Optical properties of the (Na0.5 K0.5)y Li 1-y NbO3 (y = 0.934& 0.936) ceramics have been explored in terms of the X-Ray diffraction patters,Rietveld analysis, UV-Vis spectroscopy, and Kubelka-Munk functions. Rietveldanalysis of both these structures reveals them to be tetragonal with spacegroup P4mm. It is found that increase in Li doping increases the optical bandgap. Presence of additional hardening dopant MnO2 is found to have a uniformbehavior for both these composition. With increasing MnO2 concentration, theband gap decreases indicative of increase in B-site cation and O-p orbitals.Different valences of the Mn ions and relative difference in the ionic radii ofthe Mn ions and Nb ion are most likely the reason for these optical properties.