Ferroelectricity of Li-doped silver niobate (Ag, Li)NbO3

Phase evolution in (Ag1-xLix)NbO3 (ALN) solid solution was investigated by the x-ray diffraction technique, dielectric and polarization measurements. It is shown that a small substitution of Ag with Li gives rise to an orthorhombic-rhombohedral structural transformation in ABO(3)-perovskite silver niobate at room temperature. Structural refinements indicate that both the A- and B-site displacements contribute to the spontaneous polarization of the ferroelectric phase with symmetry R3c. Increasing Li-concentration enhances the ferroelectric rhombohedral distortion, resulting in an increase of the para-ferroelectric phase transition temperature and the polarization of the solid solutions.