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Single phase perovskite ceramic Pb(Mg 1/4 Cd 1/12 Nb 2/3 )O 3 (PMCN) was prepared by the high temperature solid-state reaction method. Dielectric constant and loss tangent were measured over a frequency range 1 kHz to 1 MHz in the temperature region -40 to 115°C. Dielectric studies revealed the relaxor behaviour with diffuse phase transition. The frequency dependence of the temperature of the permittivity maximum (T m ) has been modeled using Vogel-Fulcher relation. The dielectric relaxation in PMCN is found to be analogous to the magnetic relaxation in spin-glass system. [ABSTRACT FROM AUTHOR]

Pb[(Mg 3/4 Zn 1/4 ) 1/3 Nb 2/3 ]O 3 (PMZN) ceramic was prepared by columbite precursor method. The structural analysis revealed the cubic phase of PMZN at room temperature. Dielectric studies show the relaxor behaviour with diffuse phase transition. The transition temperature (T m ) was found to be at 40°C at 1 kHz. The frequency dependence T m has been modeled using Vogel-Fulcher relation. The dielectric relaxation in PMZN is found analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in PMZN has also been examined through admittance spectroscopy. [ABSTRACT FROM AUTHOR]