Impedance spectroscopy analysis of Ba5NdTi3Nb7O30 ferroelectric ceramic

The polycrystalline sample of Ba5NdTi3Nb7O30, a member of tungsten bronze family, was prepared by solid-state reaction method. X-ray diffraction (XRD) analysis shows the formation of single-phase compound with an orthorhombic structure. Scanning electron micrograph of the material shows uniform grain distribution throughout the sample. Variation of dielectric constant (ε′r) with temperature at different frequencies shows that the compound has a dielectric anomaly of ferroelectric to paraelectric type at 100 °C, and exhibits non-relaxor kind of diffuse phase transition. Studies of electrical properties of Ba5NdTi3Nb7O30 using the complex impedance spectroscopy (CIS) technique show the decrease in bulk resistance with rise in temperature indicating a typical negative temperature coefficient of resistance (NTCR)-type behaviour. A possible hopping mechanism for electrical transport in the system is evident from the modulus analysis.