Taranova I. Raman spectra and phase transitions in the mixed crystals of KDP family

Object of study: mixed crystals of KDP family. Aim: research of the isolated structural groups influence on the mechanisms of the formation of the different low temperature phases. Methods: Raman spectroscopy; Results, novelty: polarized Raman spectra in the antiferroelectric phase in the frequency region 0 ( 3500 cm-1 have been obtained and identified; it has been establihed that the hopping processes involving a change in the position of the ammonium ions mass center modulate all internal vibrations of the NH4+ ions and librational vibration of the PO43- ions; it was experimentally proved that the position of the NH4+ ions in the mixed crystal lattice of the paraelectric phase is not fixed; it has been concluded that the dipole glass state is heterogeneous and it is collection of ferroelectric, antiferroelectric clusters and paraelectric phase. Field of implementation: state solid physics, laser spectroscopy.