Electron paramagnetic resonance study of Mn2+ and Cu2+ spin probes in (Ag2S)(x)(GeS2)(1-x) glasses

Mn2+ and Cu2+ spin probes have been introduced in glassy (Ag2S)(x)(GeS2)(1-x) (0 less than or equal to x less than or equal to 0.8). The electron paramagnetic resonance spectra related to Mn2+ show a poorly resolved hyperfine structure at g = 2 and a characteristic line at g = 4.3 ascribed to the presence of Mn2+ in the center of GeS4 tetrahedra. For small contents of Mn2+, hyperfine structure is resolved as x increases to the limit x = 0.55 and not resolved when x greater than or equal to 0.6. The Cu2+ probe leads to a well resolved signal when x = 0.4. No signal is observed for x < 0.3. These results seem to confirm the presence of a phase separation domain for x < 0.3 and the changes of the local structure of the probes with the appearance of micro-crystallinity due to the Ag8GeS6 phase when x greater than or equal to 0.55.