# Relaxor type perovskites: Primary candidates of nano-polar regions

Krupanidhi, SB (2003) Relaxor type perovskites: Primary candidates of nano-polar regions. In: Journal of Chemical Sciences, 115 (5-6). pp. 775-788.

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Relaxor properties of $0\cdot7Pb(Mg_{1/3}Nb_{2/3})O_3-0\cdot3PbTiO_3$ (PMN-PT) and non-lead perovskite thin films have been analysed in terms of large frequency dispersion of dielectric response at low temperatures. A wide spectrum of dielectric relaxation was observed in the frequency-dependent response of the imaginary part of the dielectric permittivity. Transformation from normal ferroelectric to relaxor behaviour has been observed in the case of the Ca substituting the $BaTiO_3$ thin films. A number of techniques were exploited to investigate the wide spectrum of relaxation times in pulsed laser ablated thin films. ac and dc electric field induced complex dielectric properties of $0\cdot7Pb(Mg_{1/3}Nb_{2/3})O_3-0\cdot3PbTiO_3$ (PMN-PT) thin films were studied as function of frequencies at different temperatures. Nonlinear behaviour of dielectric susceptibility with respect to the amplitude of the ac drive was observed at lower temperatures. The frequency dependence of transition temperature $T_m$ (temperature of the maximum of dielectric constant) was studied using the Vogel–Fulcher relation.