Spectroscopic and transport studies of Cu2+ doped in (30-x)Na2O-xNaF-50B2O3-20Bi2O3 glass system

ESR, optical absorption, IR and dc electrical conductivity of (30-x)Na2O-xNaF-50B(2)O(3)-20 Bi2O3 glass system have been investigated. From infrared results, it is observed that the glass is made up of [BO3] and [BO4] units and in fluorine rich glass B-F bonds are formed. ESR results show that Cu2+ has tetragonal distorted octahedral coordination and its ground state is d(x)(-y)(2)(2). The observed changes in spin-Hamiltonian parameters with increasing concentration of NaF can be attributed to the decrease in the field strength at Cu2+ ion site The decrease in alpha value can be attributed to decreasing ionic character of the glass. The existence of maxima of optical absorption at x = 18 mole% of NaF is attributed to the formation of 130,172 structural units. The de electrtrical conductivity studies show that mobile ions are Na+ and the activation energy is attaining a maximum value at x = 18 mole% of NaF characterizing a mixed anion effect.