Correlation between the piezoelectric properties and the structure of lead-free KNN-modified ceramics, studied by Raman Spectroscopy

The structure of (Li, Na, K)(Nb, Ta, Sb)O(3) piezoelectric ceramics was thoroughly studied by X-ray diffraction (XRD) and Raman spectroscopy for samples with different compositions and sintered for different times. A linear relationship is evidenced between the tetragonality ratio derived from XRD and the Raman shift. The Raman stretching modes are used to demonstrate the correlation of the structure and the piezoelectric properties of the materials, and to calculate the effective ionic displacement causing the piezoelectric polarization. The methodology proposed here offers invaluable insight into the nondestructive Raman analysis of perovskite structures based on the potassium sodium niobate systems, which are not amenable by studies of diffraction or other spectroscopic techniques. Copyright (C) 2010 John Wiley & Sons, Ltd.