RAMAN-SCATTERING STUDIES OF PB(ZRXTI1-X)O-3 AND PB1-3Y 2NDY(ZRXTI1-X)O-3 CERAMICS WITH UV AND VISIBLE LASER LIGHTS/

Raman scattering studies of lead zirconate titanate (Pb(ZrxTi1-x)O-3, PZT, 0.10 less than or equal to x less than or equal to 0.70) Nd-modif ied lead titanate (Pb1-3y/2NdyTiO3, PNT, 0.02 less than or equal to y less than or equal to 0.10) and Nd-modified lead zirconate titanate (P b1-3y/2Ndy(Zr0.53Ti0.47)O-3,O- PNZT, 0 less than or equal to y less th an or equal to 0.03) bulk ceramics using uv and visible laser lights ( wavelengths 363.79 nm and 514.532 nm, respectively) were carried out a t room temperature. In the case of uv light, Raman spectra revealed th ree or four high-frequency modes above 1000 cm(-1) in all the samples and a weak mode at around 970 cm(-1) in PNT samples. These modes do no t correspond to the first-order modes from the ideal crystal symmetrie s (C-4v(1), C-3v(1), C-3v(6)) which were the only phases revealed by t he X-ray diffraction measurements. The intensities of these modes were strongest in the trigonal phase region and decreased with decreasing Zr content. The frequency of the mode at around 1 170 cm(-1) in PZT ce ramics showed anomalous behaviour at the phase transitions between the tetragonal and high-temperature trigonal phases and between the high- and low-temperature trigonal phases. These modes probably correspond to an electronic process in the Pb3+ hole traps.