摘要
The polycrystalline sample of Li_(2)Pb_(2)Pr_(2)W_(2)Ti_(4)V_(4)O_(30) was prepared by a solid-state reaction technique.The preparation conditions of the compound have been optimized using thermal analysis(DTA and TGA)technique.Room temperature structural analysis confirms the formation of single phase compound in orthorhombic crystal system.The surface morphology of the sample,recorded by scanning electron microscope,shows uniform grain distribution on the surface of the sample.The observation of hysteresis loop confirmed that the material has ferroelectric properties at room temperature.Electrical properties of the material were studied by complex impedance spectroscopic technique.Temperature dependence of electrical parameters(impedance,modulus,etc.)is strongly correlated to the micro-structural characteristics(bulk,grain boundary,etc.)of the sample.A typical temperature-dependent resistive characteristic of the sample(i.e.,negative temperature coe±cient of resistance(NTCR))exhibits its semiconducting properties.The temperature dependence of dc conductivity shows a typical Arrhenius behavior.A signature of ionic conductivity in the system was observed in ac conductivity spectrum.The sample obeys Jonscher's universal power law.The hopping mechanism for electrical transport properties of the system with nonexponential-type conductivity relaxation was suggested from the electrical modulus analysis.
