Diffuse ferroelectric phase transition in Na2Pb2Sm2W2Ti4 Nb4O30 ceramics

The complex polycrystalline ceramic sample of Na2Pb2Sm2W2Ti4Nb4O30 was prepared by a high temperature solid-state reaction technique. Preliminary X-ray diffraction (XRD) studies of the compound showed the formation of single-phase compound in an orthorhombic crystal structure at room temperature. Studies of dielectric properties (ɛ, tan δ) of the above compound at frequencies 10, 100 and 1000 kHz and in a wide temperature range (273–700 K) exhibit a ferroelectric phase transition of diffuse type. Impedance spectroscopy study provides an insight into the electrical properties and understanding of types of relaxation process in the material. Temperature variation of dc resistivity/conductivity shows that this compound exhibits negative temperature coefficient of resistance (NTCR) at high temperature.