Electron paramagnetic resonance study of vanadium doped lead haloborate glasses

A comparable study of the EPR spectra and local structures for 3d1‐ and 3d9‐doped halo‐borate glasses

“…According to the simple g formulae in Refs. [10,12,13], the adjustable parameters α 2 , β 2 , and β 1 2 were used to indicate the covalency in the glasses. In the present work, the improved treatment is achieved based on the high-order perturbation formulae of SHPs and their concentration dependences for PbF 2 -PbO-B 2 O 3 -CuO and PbBr 2 -PbO-B 2 O 3 -CuO glasses, which is proved acceptable and accurate in other reports.…”

“…24,25 In contrast, the obtained covalency factors N show consistent tendency and close values with the previous adjustable ones in Refs. [10,12,13] and hence can be regarded as reasonable. Besides, the estimated D q by fitting SHPs for Cu 2+ in PbX 2 -PbO-B 2 O 3 glasses show the order F > Cl >Br (in Table 3), which are comparable with the spectrochemical series.…”

“…In order to understand the role of TM ions in glasses, a powerful technique that characterizes specific physical natures which are sensitive to the local environments can be realized through electron paramagnetic resonance (EPR) spectra, which reveal the microscopic local environment of TM ions in glasses, including the network, symmetries, and bonding conditions around TM ions. 10,14 It is worth mentioning that EPR has been proved highly sensitive to the paramagnetic signals of these TM impurities, which has been adopted to investigate the PbX 2 -PbO-B 2 O 3 glasses (X = F, Cl, and Br) doped with Cu 2+ (3d 9 ), 7,15 represented by the properties of g factors and hyperfine structure parameters, that is, g // > g ⊥ and A // > A ⊥ for Cu 2+ . Despite the investigation of PbCl 2 -PbO-B 2 O 3 -CuO glasses in the previous article 16 and the rough explanation based on simple g formulae with various adjustable molecular orbital coefficients α 2 , β 2 , and β 1 2 , 12,13 the local structural information of paramagnetic impurities Cu 2+ in PbX 2 -PbO-B 2 O 3 glasses (X = F and Br) need to be further studied, which is helpful to acknowledge the role for different TM dopants (Cu 2+ and V 4+ ) by united and compared study.…”

“…In PbX 2 -PbO-B 2 O 3 doped with CuO glasses, X usually represents halogen (e.g., F, Cl, and Br) ions. 10,12,13 Due to the Jahn-Teller effect, the structures around the dopants (Cu 2+ ) can be modified, characterized by distortions. 17,18 Despite the slightly different SPHs for PbX 2 -PbO-B 2 O 3 -CuO with different concentrations, the same properties g // > g ⊥ and | A // | > |A ⊥ | are satisfied at all concentrations, 10,12,13 which can be ascribed to the tetragonally elongated octahedral 3d 9 clusters 19,20 (see Figure 1).…”

“…Therefore, the comparable experiment has been carried out in Refs. [10][11][12][13], where the Cu 2+ and V 4+ ions are doped to better study the characteristics of oxyhalide glasses in optical conductors. This is because doping transition metal (TM) ions in materials usually can change the physical properties of the glasses, niobyl(3+) cation (NbO 3+ ), which enters deform dra (octahedra, tetragonal pyramids) with a co covalent bond to oxygen.…”