Ionic conductivity and structural properties of MnO-doped Bi4V2O11 system

Bi4V2O11 exists in three phases viz. alpha, beta, and gamma. High temperature gamma-phase can be stabilized to room temperature owing to its higher conductivity by the partial substitution of metallic cations for vanadium in Bi4V2O11. Phase transitions from alpha -> beta and beta -> gamma are composition and temperature-dependent. Mn2+-doped compounds Bi4V2-x Mn (x) O11- (delta) (0 a parts per thousand currency signaEuro parts per thousand x a parts per thousand currency signaEuro parts per thousand 0.4) have been synthesized by solid state reaction technique and investigated by X-ray diffraction and ionic conductivity measurement. High ionic conducting gamma-phase is stabilized for x a parts per thousand yenaEuro parts per thousand 0.2. The ionic conductivity of the series of Bi4V2-x Mn (x) O11- (delta) samples has been measured by using ac impedance spectroscopy technique. The conductivity data do show departure from its simple Arrhenius behavior for all of the compositions. The highest conductivity observed for x = 0.2 sample can be attributed to lower activation energy.