Effect of Cu–Al double substitution on the electrical properties of Bi₄V₂O₁₁

Abstract

Bi 2 Cu 0.1¡x Al x V 0.9 O 5.35¡x/2¡d , 0.02 x 0.08, were synthesized by standard solidstate reaction route. Structural and electrical properties of samples are characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), Fourier transform infrared (FT-IR) and alternating current (AC) impedance spectroscopy. The tetragonal g 0 phase structure is preserved to room temperature with compound x D 0.02. The stabilization of b orthorhombic phase is observed for compositions 0.04 x 0.05. As the Al content increases, the monoclinic a phase is evidenced for materials 0.06 x 0.08. The electrical investigation of Bi 2 Cu 0.1¡x Al x V 0.9 O 5.35¡x/2¡d system has been performed in the frequency range from 20 Hz to 1 MHz using AC impedance spectroscopy. The impedance spectra indicate the two semicircle arcs associated with the bulk and grain boundary resistances at temperature below »450 C. The conductivity generally changes when Al is substituted. The highest conductivity at 300 C (s D 2.55 £ 10 ¡4 S cm ¡1 ) is shown for x D 0.02.

AC impedance spectroscopy and conductivity studies of Dy doped Bi4V2O11 ceramics

“…At higher frequency, it is clear that there is an absence of space charge effect in the materials. Similar type of behavior is also observed in other studied material [16].…”

“…X-ray diffraction analysis of the calcined homogenous fine powders were studied at room temperature using a diffractometer (ULTIMA IV Model-Rigaku, Japan) using CuKa radiation (k = o , which suggests the b phase orthorhombic crystal structure at room temperature [16]. A good agreement between observed (obs) and calculated (cal) inter-…”