Glass-like response of (Na1/2Bi1/2)TiO3–WO3 ceramic

Polycrystalline sample of 2.5 wt% WO3 added (Na1/2Bi1/2)TiO3 was prepared using a high-temperature solid-state reaction method at 1050 C and subsequent sintering at 1090 C in oxygen atmosphere. XRD analysis indicated the formation of a single-phase orthorhombic structure. Dielectric studies revealed the relaxor behaviour. The addition of WO3 to NBT shifts phase transition temperature as well as depolarization temperature to higher side which is desirable for piezoelectric applications. The frequency dependence of the temperature of the permittivity maximum has been modeled using Vogel–Fulcher relation. The dielectric relaxation in the system is found to be analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in the present system has also been examined through admittance spectroscopy.