Structural and impedance properties of Ba_5DyTi_3V_7O_(30)

摘要

A polycrystalline sample of Ba_5DyTi_3V_7O_(30) (BDTV) was prepared by a mixed-oxide method at 1,000 ℃ (sintering temperature). Preliminary X-ray structural analysis confirmed a single-phase formation of the compound. Scanning electron micrograph of the material show uniform distribution of grains of different shape and size on the surface of the sample. Detailed studies of dielectric properties in a wide range of temperature (30-400 ℃) and frequencies (10~3-10~6 Hz) exhibit ferroelectric (diffuse) phase transition, which was confirmed by appearance of hysteresis loop at room temperature. Electrical properties (impedance properties) of the material were obtained using a complex impedance technique. The Nyquist plots confirmed the contribution of grain in the material. Studies of electrical conductivity (both dc and ac) over a wide temperature range suggest that the compound exhibits the negative temperature coefficient of resistance behavior. The ac conductivity spectra were found to obey Jonscher's universal power law.