EPR spectra of Mn 2+ doped CdX 2PbY 2KI (X, Y = Cl, Br) glasses

Abstract

Electron paramagnetic resonance (EPR) spectra of glasses of five compositions: 1. I, (CdCl 2) 0.3(PnCl 2) 0.6(KI) 0.1; 2. II, (CdCl 2) 0.3(PbCl 2) 0.5(KI) 0.2; 3. III, (CdCl 2) 0.3(PbBr 2) 0.5(KI) 0.2; 4. IV, (CdCl 2) 0.2(PbBr 2) 0.6(KI) 0.2; and 5. V, (CdBr 2) 0.2(PbBr 2) 0.6(KI) 0.2 doped with MnCl 2 and MnBr 2 at concentrations from 0.1 to 3.0 mol% were investigated. An intense g eff ≊ 2.0 resonance was found in all glasses studied; the other resonances, g eff ≊ 4.3 and g eff = 3.3, changed their intensities in relation to the g eff ≊ 2.0 resonance in dependence on the composition of the host glasses. Most of the magnetically active centres of impurity Mn 2+ ions with the g eff ≊ 4.3 were assumed to be tetragonally distorted octahedrons that could be described by fourth order spin Hamiltonian. The assumption was supported by temperature behavior of intensities of the g eff ≊ 4.3 resonance. The local structure of most of the magnetically active Mn 2+ centres in glasses with a higher amount of bromide atoms was supposed to be of lower symmetry than the local structure of centres with chloride atoms. The assumption was supported by decrease of intensity of the g eff ≊ 2.0 resonance in relation to the intensity of the other resonances, the g eff ≊ 3.3 and the g eff ≊ 4.3 , in series from chloride through mixed to bromide glasses. The optical spectra of pure and Mn 2+ doped glasses were measured from visible to far infrared region and both kinds of spectra were indistinguishable.