Diffuse phase transition characteristics and relaxor behavior of lanthanum doped lead titanate thin films

Room temperature micro-Raman scattering, P-E hysteresis and temperature dependent dielectric measurements were carried out on sol-gel derived ferroelectric Pb1-xLaxTiO3 (PLT x = 0.0 to 0.30) thin films. micro-Raman results indicate that the crystal structure of the PLT films was strongly influenced by the La contents. The dielectric properties of PLT thin films were studied in the temperature range 80 700 K and frequencies (1 kHz - 1 MHz). Results indicate that PLT thin films undergo normal-to-relaxor ferroelectric transformation with 30 at% La content in PLT films. The observed behavior is evaluated in terms of diffuseness and Vogel-Fulcher relationship, which is typical for relaxor ferroelectrics.