LARGE FARADAY-EFFECT AND LOCAL-STRUCTURE OF ALKALI SILICATE-GLASSES CONTAINING DIVALENT EUROPIUM IONS

Measurements of Faraday and Mossbauer effects have been performed at r oom temperature for alkali silicate glasses containing a large amount of Eu2+ ions to examine the relation between local structure and magni tude of Verdet constant. The Mossbauer spectra indicate that about 80% of europium ions are present as a divalent state. The effective trans ition wavelength and effective transition probability for the 4f(7) -- > 4f(6)5d transition of Eu2+, which causes the Faraday effect, are der ived from the wavelength dependence of Verdet constant. Both effective transition wavelength and effective transition probability are large compared with berate glasses; leading to the large magnitude of Verdet constant of the alkali silicate glasses. The variation of effective t ransition wavelength with glass composition is connected with the chan ge of 6s-electron density of Eu2+ evaluated from the Mossbauer spectro scopy.