Evolution of polar order in (1 - x)Pb(In1/2Nb1/2)O3-xPbTiO3 (0 ≤ x ≤ 1) system as investigated by dielectric and Raman spectroscopy

摘要

We have investigated the (1 - x)Pb(In1/2Nb1/2)O3 - xPbTiO3 (PIN-PT) solid solution by Raman scattering and temperature variation of dielectric measurement. The dielectric analysis indicates that the Burn's temperature (TB) raises upto x = 0.30 and then decreases due to the enhancement in the long range ferroelectric order. At x = 0.60, TB coincides with the temperature at which dielectric constant is maximum, Tm, (TB ∼ Tm). It suggests that the polar nanoregions (PNRs) are not present in 0.40PIN-0.60PT. The investigation confirms that PT addition in PIN transforms the PNRs into the macroscopic ferroelectric domains. The composition dependent Raman spectra are used to interpret the evolution of polar order. Qualitative Raman analysis reveals that the changes in the vibration bands are associated with the structural transition from R3m to P4mm at morphotrophic phase region. For the values of x > 0.41, the line-width of all the bands decreases as the concentration of PT increases. The observed two mode behavior in the highest frequency region (800 cm-1) hints the existence of chemical inhomogenetiy at nanometer scale such as the local segregation of Ti and In/Nb-rich regions.