Dopant and milling time effect on impedance and electrical properties of perovskite ceramics

Tungsten doped Barium Titanate (BT) with composition BaW۰.۰۵Ti۰.۹۵O۳ (BWT) were prepared by using ball milling technique for different hours (۱۰h, ۲۰h and ۳۰h). In the present paper, the microstructural, dielectric and impedance studies are discussed. The microstructural studies using XRD data reveals the formation of single phased tetragonal structure and perovskite structure. The dielectric properties of BT nanoceramics were significantly enhanced by the partial replacement of W (at B site) showing the diffuse phase transition at ۸۰°C. Dielectric loss rises as the temperature rises. There is increase in charge carrier mobility which results in increased polarization and significant dielectric loss. Additionally, compared to the un-milled BWT ceramic sample, the ۳۰h milled had superior dielectric characteristics with high dielectric constant and reduced loss. The nature of the phase transition was confirmed by the Curie-Weiss law and the ferroelectric analysis was carried by well-established P-E loops. The impedance studies were carried out by plotting Nyquist plots. The ac conductivity plot follows Arrhenius relation and the calculated activation energy confirms the negative temperature coefficient of resistance (NTCR) behavior of the material.

کلیدواژه ها:

ferroelectrics ، barium titanate ، XRD ، SEM ، PE