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

摘要

Bi2Cu0.1-xAlxV0.9O5.35-x/2-delta, 0.02 <= x <= 0.08, were synthesized by standard solid-state 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 gamma ' phase structure is preserved to room temperature with compound x = 0.02. The stabilization of beta orthorhombic phase is observed for compositions 0.04 <= x <= 0.05. As the Al content increases, the monoclinic alpha phase is evidenced for materials 0.06 <= x <= 0.08. The electrical investigation of Bi2Cu0.1-xAlxV0.9O5.35-x/2-delta 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 similar to 450 C-White circle. The conductivity generally changes when Al is substituted. The highest conductivity at 300 C-White circle (sigma = 2.55 x 10(-4) S cm(-1)) is shown for x = 0.02.