Optical Detection of Paramagnetic Centres in Activated Oxyfluoride Glass-Ceramics

Abstract

Electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD) and EPR detected via MCD (MCD-EPR) investigations have been performed on rare-earth activated oxyfluoride glasses and glass-ceramics. Er 3+ , Gd 3+ , and Mn 2+ activators in oxyfluoride glass-ceramics show paramagnetic MCD behaviour and the MCD-EPR has been detected. The results of the MCD-EPR measurements for the Er-doped oxyfluoride glass-ceramics showed that Er 3+ ions in the CaF2 crystallites in these ceramics embed only in the cubic symmetry environment, similarly to the previous observations of cubic Gd 3+ centres in the glass-ceramics containing CaF2. Finally, the correlation of optics and paramagnetic centres is discussed for Mn-doped YAlO3 ceramics.

EPR characterization of erbium in glasses and glass ceramics

“…Oxyfluoride samples synthesized by the melt quenching technique of the following compositions have been investigated: 19NaO2-7BaF2-7YF3-6Al2O3-60SiO2-1ErF3 (BYF), 19NaO2-7NaF-7YF3-6Al2O3-60SiO2-1ErF3 (NYF) [11] and 8CaCO3-25.4CaF2-20.5Al2O3-46SiO2-0.1Er2O3 (CF) [24]. CF glass ceramics have been obtained by an isothermal heat treatment at 700 °C for 1 h. EPR spectra were measured at 10 K with Bruker ELEXSYS-II E500 CW-EPR spectrometer equipped with a liquid helium flow cryostat.…”

“…6. MCD spectrum of erbium doped oxyfluoride glass ceramics containing CaF2 nanocrystals detected at 1.5 K and 1 T. Inset shows 62 GHz MCD-EPR spectra of the glass ceramics and respective glass samples measured at 521 nm MCD band [24].…”

“…4). It can be concluded that a part of Er 3+ ions incorporate the crystalline phase of glass ceramics and contribute to the 4 I15/2 → 2 H11/2 MCD transition [24].…”

EPR in glass ceramics

“…Incorporation of Er 3 + in a cubic environment of the CaF 2 crystalline phase has been reported in oxyfluoride glass ceramics [89]. In this particular study, the EPR signal was detected optically on a magnetic circular dichroism (MCD) band.…”