The Influence of low Ammonium Concentration in Ferroelectric-Antiferroelectric Mixed crystals Rb1-x(ND4)xD2AsO4 by Raman Scattering

• Main Author: 高旭伸
• Other Authors: 杜繼舜
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/18603541340479496285

碩士 === 輔仁大學 === 物理學研究所 === 85 === The Raman spectra of Rb1-x(ND4)xD2AsO4 (DRADA-x=0.10, 0.28 and 0.38) mixed crystals have been studied in the temperature range 80-300 K for three fundamental geometries; A1-y(zz)x, B2-y(xy)x and E-y(xz)x for frequency range 50-1050 cm-1. The spectra have been interpreted in terms of vibrational modes and compared with the previous results. We have concentrated on the vibrations related to the internal modes of the AsO4 moleclar groups. In this type of mixed crystal, competition between the ferroelectric (FE) and the antiferroelectric (AFE) orderings plays an important role for the temperature dependent behavior of internal vibrational modes. At low temperature region, the system forms so called glass state due to the random distribution of Rb+ and ND4 (or NH4) ions that can produce frustration and suppress the long-range electric order.