Na1xLixNbO3 ceramics with composition 0.05 r x r 0.30 were prepared by solid-state reaction method
and sintered in thetemperature range 1100–1150 C. These ceramics were characterised by X-ray
diffraction as well as dielectric permittivity measurements and Raman spectroscopy.Dielectric
properties of ceramics belonging to the whole composition domain were investigated in a broad range
of temperatures from 300 to 750 K and frequencies from 0.1 to 200 kHz.The Rietveld refinement
powder X-ray diffraction analysis showed that these ceramics have a single phase of perovskite
structure with orthorhombic symmetry for x 0.15 and two phases coexistence of rhombohedral and
orthorhombic above x=0.20. The evolution of the permittivity as a function of temperature and
frequency showed that these ceramics Na1xLixNbO3 with composition 0.05rxr0.15 present the
classical ferroelectric character and the phase transition temperature TC increases as x content
increases.The polarisation state was checked by pyroelectric and piezoelectric measurements.For
x¼0.05, the piezoelectric coefficient d31 is of 2pC/N.The evolution of the Raman spectra was studied as
a function of temperatures and compositions.The results of the Raman spectroscopy study confirm our
dielectric measurements ,and they indicate clearly the transition from the polar ferroelectric phase to
the non-polar paraelectric one