Complex impedance spectroscopy study was done on 0.91Pb(Zn 1=3 Nb 2=3 )O 3 -0.09PbTiO 3 (PZN-PT) single crystals in the wide range of temperatures (25-525 C) and frequencies (1 kHz-1 MHz). The ac conductivity was computed from the impedance data and the activation energy for conduction at different frequencies was determined. Frequency explicit plots of imaginary components of impedance exhibit Debye-like peak shapes. Cole-Cole diagrams were observed in the high temperature regime. Temperature dependent conductivity measurement and Cole-Cole plots fairly establish the existence of quenched random defects in the PZN-PT system.

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