Debnath, Radhaballabh (2001) Thermally reversible gamma-ray-induced redox reaction between substitutional iron and aluminum impurity centers in a silica glass. Journal of Materials Research, 16 (1). pp. 127-131. ISSN 0884-2914

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The magnetic properties of the substitutional iron and aluminum impurity centers in a sintered Vycor silica glass were studied before and after 1.1-1.3 MeV gamma irradiation. Observation of two overlapping spin resonances (g similar to 4.20-4.28) in the spectra of both the irradiated and preirradiated glasses indicated the existence of two types of tetra coordinated substitutional iron centers of the [FeO(4)(-)/Na(+)](0) type. The intensity of these electron-paramagnetic resonance (EPR) signals decreased upon gamma irradiation of the glass with concomitant generation of aluminum hole center [AlO(4)](0), which was manifested by the occurrence of a new six-line EPR signal with g = 2.009, while thermal annealing of these aluminum oxygen hole centers restores the intensity of the iron centers almost to their preirradiation level. This result suggests that if not the whole, a major fraction of the electrons released in the process of gamma -ray-induced hole trapping at the Al site are captured by the substitutional iron centers. The electron traps, thus formed, are quite stable and can be deactivated by thermal stimulation.

Item Type: Article
Subjects: Glass
Divisions: Glass
Depositing User: Bidhan Chaudhuri
Date Deposited: 29 Mar 2012 08:38
Last Modified: 05 Mar 2016 15:33

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