Dielectric dispersion and vibrational studies of a new ferroelectric, glycinium phosphite crystal

The dielectric dispersion in glycine phosphite crystal over the frequency range 30-1000 MHz is presented. Ferroelectric dispersion of the Debye type along the b-axis occurs in the microwave-frequency region and is caused by a single relaxational soft mode. The powder IR (at low temperatures between 300 and 14 K) and FT Raman spectra in the region between 4000 and 80 cm(-1) are measured. DSC measurements for the GPI and deuterated crystals are performed. The results confirm the order-disorder nature of a proper ferroelectric phase transition of second order.