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Glasses doped with transition metal (TM) ions exhibit rich optical transitions spanning the entire ultraviolet, visible, and infrared spectral regimes. Here we utilize the melt-quenching techniques to synthesis binary-TM-doped borate glasses of composition xCuO-(75-x)B2O3-24.7Li2O-0.3Cr2O3, with x = 0, 0.2, 1.0 and 2.0 mol %. We identify several optical transitions from Cr3+, Cr6+, and Cu2+ ions, the latter manifests at longer wavelengths and gains higher intensity with Cu additives. Despite Cr concentration being fixed, the Cr6+ peaks are quenched and Cr3+ signals are barely attenuated. This behavior rules out possible phase separation and suggests non-trivial interplay between the two TM ions and ligand, as supported by probing their oxidation states from electron spin resonance. The crystal field and Racah parameters followed an opposite behavior, while the optical band gap is reduced upon doping. These changes are correlated with structural modifications introduced by Cu additives, where we anticipate homogenous and preferential proximity of Cu-Cr ions within the network.

Articles you may be interested inThe effect of annealing on the structural and magnetic properties of zinc substitutes Ni-ferrite nanocrystals AIP Conf. Proc. 1512, 286 (2013); 10.1063/1.4791023Inter particle interaction in Ni0.5Zn0.5Fe2O4 prepared by self combustion method AIP Conf.Abstract: Mixed ferrite system of com position Ni x Fe 3-x O 4 Where ( x= 1,1.25,1.5,2) (inverse spinel) has been prepared in nano form. Ni and Fe nitrates are mixed and shacked thoughrly, then NaOH has been used as a precipitating agent. Obtained samples were washed by the ionized water and ethanol. Finally dried at 70 o C for one day the ingots have been annealed at different temperatures . XRD and ME spectra have been measured. It was found that the particle size increases by increasing annealing temperature. All samples annealed at T ≤ 650 o C show superparamagnetic effects, Samples annealed at 900,1000 o C exhibit magnetic hyperfine interaction reflecting high magnetic moments.