Local structure and kinetics of paramagnetic defects, induced by γ-irradiation of the erbium doped Ag5Ga5Ge95S200 glasses

Abstract

Defects induced by γ-irradiation in Er-free and Er-doped glasses Ag5Ga5Ge95S200 were studied using the Raman and EPR spectroscopies. It is shown that γ-irradiation causes an increase in the intensity of Raman bands related with formation of S3Ge-GeS3 structural groups. During the low-temperature annealing at temperatures of 95–145 °C, the concentration Ns of γ-induced paramagnetic centres (PC), having the axial symmetry of the g-tensor with gz = 2.0180 and gx = gy = 2.0088, is being strongly reduced and the symmetry of the environment of these centres becomes lower. Subsequent storage of annealed samples in the air for about 15 days leads to a gradual restoration of the Ns concentration. The kinetics of these processes is described taking into account both the high mobility of sulfur vacancy and the long-time relaxation of the glass structure. A correlation between the intensity of 257 cm−1 Raman band belonging to the S3Ge(Ga)-(Ga)GeS3 complex and PC characteristics is discussed.