Title :
Optical mode softening of ferroelectric SrBi2(Nbx Ta1-x)2O9 system
Author :
Kojima, Seiji ; Saitoh, Itaru ; Yamamoto, Takashi
Author_Institution :
Inst. of Appl. Phys., Tsukuba Univ., Ibaraki, Japan
Abstract :
The vibrational properties of the ferroelectric phase transitions of the SrBi2(NbxTa1-x)2O9 ceramic system (x=0, 1/3, 2/3, 1) have been studied by Raman spectroscopy in the temperature range from room temperature up to 500°C. For all compositions the lowest optical modes indicate the remarkable temperature dependence towards Tc and disappear above Tc. Their damping factors increase rapidly towards T c, while the softening of mode frequency is relatively small. The composition dependence of the rigid-sublattice mode amid the symmetric stretching mode of oxygen octahedra has been discussed
Keywords :
Raman spectra; bismuth compounds; ferroelectric Curie temperature; ferroelectric ceramics; ferroelectric transitions; phonon spectra; soft modes; strontium compounds; 20 to 500 C; Raman spectroscopy; SrBi2(NbTa)2O9; Tc; ceramic; composition dependence; damping factors; ferroelectric SrBi2(NbxTa1-x) 2O9 system; ferroelectric phase transitions; optical mode softening; oxygen octahedra; rigid-sublattice mode; room temperature; symmetric stretching mode; temperature dependence; vibrational properties; Ceramics; Damping; Ferroelectric materials; Frequency; Niobium; Raman scattering; Softening; Spectroscopy; Temperature dependence; Temperature distribution;
Conference_Titel :
Applications of Ferroelectrics, 1998. ISAF 98. Proceedings of the Eleventh IEEE International Symposium on
Conference_Location :
Montreux
Print_ISBN :
0-7803-4959-8
DOI :
10.1109/ISAF.1998.786734
