EPR of γ-induced paramagnetic centers in tellurite glasses

Abstract

Intrinsic paramagnetic responses were observed in the 60TeO 2 -25ZnO-15Na 2 O and 85TeO 2 -15Na 2 O mol% glasses, after γ-irradiation at room temperature: (1) a shoulder at g 1 = g ∥ = 2.02 ± 0.01 and an estimated g ⊥~2 .0 attributed to tellurium-oxygen hole center (TeOHC); (2) a narrow resonance at g 2 = 1.9960 ± 0.0005 related to the modifiers and (3) a resolved resonance at g 3 = 1.9700 ± 0.0005 ascribed to a tellurium electron center (TeEC) of an electron trapped at an oxygen vacancy (V O + ) in a tellurium oxide structural center. It is suggested that the creation of (NBO − ,V O + ) pair follows a mechanism where the modifier oxide molecule actuates as a catalyser. An additional model for the NBO radiolysis produced by the γ-irradiation is proposed on the basis of the evolution of the g 1 , g 2 and g 3 intensities with increasing dose (kGy). Crown

EPR of γ-induced defects and their effects on the photoluminescence in the glasses of the Ag0.05Ga0.05Ge0.95S2–Er2S3 system

“…Literature sources give some results of the defects studying by using electron paramagnetic resonance (EPR) (Giehl et al, 2010;Ramana et al, 1989;Lagomacini et al, 2011) and spectra of optical absorption in γ-irradiated glasses (Singh et al, 2008;Xia et al, 2005;Shpotyuk et al, 2005). However, there are only a few works devoted to the influence of γ-irradiation on creation of defects that make a considerable effect on spectralluminescent properties of semiconductor materials doped with erbium.…”

Study of sodium tellurite glass using the thermally stimulated depolarization current technique (TSDC)

“…4). A better understanding of the thermal behavior of the defect states in the tellurite glass was obtained from a recent EPR study of the isochronal thermal decay of the g 1 , g 2 and g 3 resonances recently attributed by Giehl et al [11] to the tellurium oxygen hole center (TeOHC), to the non-bridging oxygen hole center (NBOHC), and to the tellurium electron center (TeEC), respectively as it is shown in Fig. 5.…”

Optical properties and weakening of elastic moduli with increasing glass transition temperature (T g) in (80–x)TeO2-xBaO-20ZnO glasses

“…Previous studies reported that NBO not only exhibits higher polarizability than BO but also binds excited electronsmore loosely than BO; as such, NBO requires lower energy to induce electron excitation than BO, resultingi nadecrease in E opt witha n increase in NBO [38,71]. In amorphous systems, E u is used to characterize the degree of disorder, which may be due to oxygen vacancies as aresult of volatilization loss of oxygen duringg lass melting or other types of defects originating from the presence of NBO [72,73]. In amorphous systems, E u is used to characterize the degree of disorder, which may be due to oxygen vacancies as aresult of volatilization loss of oxygen duringg lass melting or other types of defects originating from the presence of NBO [72,73].…”