MORPHOTROPIC PHASE-TRANSITION STUDIES IN PB(ZRXTI1-X)O-3 BY FAR-INFRARED REFLECTANCE SPECTROSCOPY

The morphotropic phase transition in the Pb(ZrxTi1-x)O-3 system has be en studied by far-infrared reflectance spectroscopy. The reflectance m easurements are performed on compositions with x = 0.0, 0.10, 0.20, 0. 30, 0.35, 0.40 and 0.525 at room temperature in the frequency range 40 -600 cm(-1). The spectrum is fitted with a model based on the factoriz ed form of the dielectric function. The dependences of the mode freque ncies, damping and oscillator strength on x are reported. The static d ielectric constant is calculated from the frequencies obtained from th e fitting. The observed experimental data show incomplete softening of the lowest E(ITO) mode towards the morphotropic phase boundary. The o scillator strength of the lowest mode carries nearly all the contribut ion to the lattice part of the dielectric constant.