Dinuclear manganese centers in the manganese-lead-tellurate glasses

FTIR, UV-VIS and EPR spectra of manganese doped lead-tellurate glasses with composition xMnO center dot(100 - x)[4TeO(2)center dot PbO2] where x=0, 1, 5, 10, 20, 30, 40 mol% have been studied. The FTIR spectra show the formation of the Mn-O-Pb and Mn-O-Te bridging bonds by increasing of MnO concentration. The UV-VIS spectra show the Mn+3 species exhibit pronounced absorption, which masks the Mn+2 spin-forbidden absorption bands when Mn+2 ions are in high concentrations in these glasses. The EPR spectra exhibit resonance signals characteristic of Mn+2 ions. The resonance signal located at g approximate to 2 is due to Mn+2 ions in an environment close to octahedral symmetry, whereas the resonance at g approximate to 4.3 and 3.3 are attributed to the rhombic surroundings of the Mn+2 ions. The increase in the MnO content gives rise to absorption at g approximate to 2.4 and the paramagnetic ions are involved in dinuclear manganese centers. (C) 2011 Elsevier B.V. All rights reserved.