Impedance spectroscopic studies of bixbyite and hausmannite crystallites

This paper focusses on impedance analysis of the different phases of oxides of manganese, prepared by solution combustion method using mixture of urea and glucose as fuels. The frequency dependence of real part of dielectric constant (ε’), dielectric loss (ε"), loss tangent (tan δ), electrical modulus (M’ and M") and ac electrical conductivity (ζac) have been investigated by impedance spectroscopy analysis. While the values of dielectric constant, dielectric loss, loss tangent and ζac decrease, the values of elastic modulus increase for the prepared samples when frequency was increased. It has been observed that, Mn3O4 (hausmannite) crystals exhibits higher dielectric constant in comparison with Mn2O3 (bixbyite). The decrease in permittivity and dielectric loss with increase in applied frequency is in accordance with Maxwell Wagner theory