X-Ray Analysis and Dielectric Characterization of Bismuth Layered (Bi2O3) (Baxfe1-Xo3) Nanocrystalline Ceramic

Polycrystalline ceramics of bismuth layered structure of (Bi2O3)(BaxFe1-xO3) (0.2x0.8, x is in step of 0.2) have been prepared by conventional solid-state reaction method to study its modified dielectric and electrical properties. X-ray diffraction technique is used on the powdered samples for physical characterization and an average grain size of 16 – 21 nm was obtained. The XRD analysis reveals the single phase structure of the sample. Dielectric properties, viz, dielectric constant (ε ́), dielectric loss (tan δ) and ac electrical conductivity of the ceramic sintered at various temperatures have been studied in the frequency range 10 -1 -10 7 Hz. The frequency and temperature dependent conductivity investigations have been carried out by using impedance spectroscopy. It was observed that the sample exhibit bulk conduction which increase with increase in temperature and with the increase in barium (Ba) concentration. The conductivity mechanism at room temperature shows a frequency dependence, which can be ascribed due to the presence of oxygen vacancies. Combined impedance and modulus plots were used to analyze the sample behavior as a function of frequency and temperature. The effect of temperature on the scaling of dielectric modulus indicates that the conductivity relaxation mechanism is temperature independent. The overlapping of the normalized peaks corresponding to impedance and electrical modulus suggests the single mechanism for the dynamic processes occurring in the present ceramics. The dielectric and conductivity properties of this ferroelectric ceramic make it a promising material for fatigue resistance in device applications.