Temperature and frequency dependent electrical conductivity and dielectric relaxation of mixed transition metal doped bismuth-phosphate semiconducting glassy systems

Abstract

Two ternary and three quaternary glass nanocomposites with a general chemical formula 0.45Bi2O3 - 0.15P2O5 - (0.4-x) V2O5- xMoO3 (x = 0, 0.1, 0.2, 0.3, and 0.4) are synthesized through melt quenching method. Few nanophases Bi5PO10, V2O5, BiVO4, Bi12P2O23, Bi(PO3)3, Bi13Mo4VO34, Mo4O11, MoOPO4, Bi4MoO9, and BiP5O14 are superimposed within glass matrices acknowledged from XRD patterns. The Almond-West formalism is used to study the electrical conductivity of mixed transition metal-doped bismuth-phosphate glass nanocomposites. The semiconducting non-linear characteristics are established from the dc conductivity curve and the different values of activation energies in high and low-temperature regions. The dc conductivity of each glass nanocomposite has been explained by the Mott and Greaves's variable range hopping model. The reducing nature dc conductivity with the rise of MoO3 content is elucidated from the estimated values of small polaron hopping energy (Whop) and hopping distance (Rhop). Modified correlated barrier hopping model flawlessly defines the mechanism of ac conductivity as the value of power-law exponent reduces with temperature. The effect of temperature and frequency on the dielectric properties of the samples has been intensely investigated. Non-Debye type of relaxation process of dynamic conductivity is predicted and the relaxation time exhibits Arrhenius characteristics.