Acoustic anomalies in diglycine-nitrate

Abstract The behaviour of some elastic constants of diglycine nitrate across the ferroelectric phase transition were measured with Brillouin scattering. The results were compared with low frequency behaviour of one elastic constant. Results were analysed in the framework of Landau free energy expansion. Discrepancy was found between the relaxation time for the spontaneous polarization from dielectric measurements and our results.