TEMPERATURE-DEPENDENCE OF HOMOGENEOUS LINE-WIDTH OF EU3-ALUMINA STUDIED BY FLUORESCENCE LINE NARROWING SPECTROSCOPY( IN BETA')

We have measured the temperature dependence of the homogeneous spectra l line width Gamma(h) of Eu3+ in beta('')-alumina, which is a typical superionic conductor, using fluorescence line narrowing spectroscopy, and have discussed dephasing mechanisms of luminescence from Eu3+ ions in this system. Due to the structural disorder in the two-dimensional conduction planes of beta('')-alumina crystals, the temperature depen dences of Gamma(h) Eu3+ ion in both Beevers-Ross (BR) and mid-oxygen ( mO) sites are essentially the same as those previously observed in gla ssy materials. However, the Eu3+ concentration as well as the temperat ure dependences of Gamma(h) of the Eu3+ ion in the mO site are quite d ifferent from those in the BR site. This fact strongly indicates that the dominant dephasing mechanisms of Gamma(h) of Eu3+ ion in these two sites are different from each other. This result is attributed to the intermediate nature of beta('')-alumina between ordered and disordere d materials.