Probing the ferroelectric phase transition through Raman spectroscopy in Pb(Fe2/3W1/3)1/2Ti1/2O3 thin films

The present work investigates the evolution of micro-Raman spectra of (1-x)Pb(Fe2/3W1/3)O-3-xPbTiO(3) (PFWT) (x=0.50) thin films in the temperature range from 80 to 600 K. Raman and dielectric data indicate that the crystal structure changes from tetragonal to cubic, i.e., a ferroelectric phase transition at 575 K. The dielectric properties of PFWT thin films were studied in the temperature range of 80-600 K over a wide range of frequencies. The slope of the reciprocal of the dielectric constant is 2:1, matched well with the simplest Landau free energy model, and it indicates a continuous second order displacive ferroelectric phase transition. (c) 2007 American Institute of Physics.