Raman scattering investigations of the low‐temperature phase transition of NaNbO3

In this work, we report the low-temperature phase transition of sodium niobate (NaNbO3) ceramics at the antiferroelectric–ferroelectric phase studied by the Raman scattering technique over the temperature range 10–300 K. The spectral shape indicates that the phase transition occurs at 160 K on the cooling cycle and at 260 K on heating. The recorded spectra are discussed following the separation of modes into the internal stretching modes of the NbO6 octahedron and Na+ cation translational modes. The 62 and 75 cm−1 peaks are proposed as the translational modes of Na+ cation against the NbO6 octahedron. Copyright © 2006 John Wiley & Sons, Ltd.