Electron paramagnetic resonance and optical absorption spectra of Gd³⁺ ions in alkali cadmium borosulphate glasses

Abstract

Electron paramagnetic resonance (EPR) at 9.205 GHz is examined for a series of Gd3+-doped alkali cadmium borosulphate (R,SO, . CdSO, . B,03; R = Li, Na, K or Cs) glasses. The spectra are similar to the U-spectra familiar in many oxide, fluoride, and sulphate glasses, indicating very low and disordered site symmetries with a broad distribution of crystal fields. Remarkable changes are observed in the spectrum with changes in temperature, glass composition, and concentration of Gd3+ ions. Optical absorption spectra of Gd3+-doped cadmium borosulphate glass are also studied at 300 K. Fur eine Reihe von Gd3'-dotierten Alkali-Kadmium-Borsulphatglasern (R,SO, . CdSO, . B,O, mit R = Li, Na, K, Cs) wird die paramagnetische Elektronenresonanz bei 9,205 GHz untersucht. Die Spektren sind den U-Spektren von Oxyd-, Fluorid-und Sulphatglasern ahnlich, was auf sehr niedrige und ungeordnete lokale Symmetrie mit.einer breiten Verteilung des Kristallfeldes hinweist. Die Spektren zeigen auffallende hderungen mit Anderungen der Temperatur, der Zusammensetzung und der Gd3+-Dotierung. Optische Absorptionsspektren von Gd3 + -dotiertern Cd-Borsulphatglas bei 300 K werden ebenfalls untersucht.

The local field distribution of in transition metal fluoride glasses investigated by electron paramagnetic resonance

“…The agreement between observed and calculated spectra seems to be better than with the distribution proposed by Brodbeck and Iton [1], which is generally considered as the only solution for the U spectrum [9][10][11][13][14]. In contrast to this previous interpretation, the distribution P (b 0 2 , λ) yields zero probability for λ = 0.…”

“…At X band (figure 2), a broad line whose intensity increases with concentration and temperature is superimposed on a narrower one at g = 2. When temperature decreases, the increase of the amplitude ratio for the g = 5.9 to g = 2 peaks has been observed in oxide glasses [9,12] and in zeolites [16]. Similar concentration and temperature dependences of the broad g = 2 line have been noted for Cr 3+ and Fe 3+ ions in TMFG.…”

“…The rare-earth S-state ion, Gd 3+ , in glassy hosts (phosphate [7,8], borosulphate [9], oxy-halo borate [10], silicate [11][12], lead acetate [13], ZnF 2 -BaF 2 -RF 3 [8], fluorozirconate [14]) routinely exhibits an X-band EPR spectrum characterized by three prominent features with effective g-values of ∼5.9, 2.8 and 2.0. This spectrum is labelled the U spectrum because of its 'ubiquity' and Gd 3+ ions are frequently suspected to impose their environment, when present as impurities in glass systems [9-11, 13, 15].…”