Anelastic and dielectric loss in yttrium-doped calcium fluoride

Abstract

A small anelastic loss peak appears in yttrium-doped calcium fluoride, being in the kc range at 350°C. Its location is dependent on specimen orientation, and the variation is consistent with the expected behavior of elastic dipoles formed from interstitial fluorine bound to the yttrium in nn or nnn positions. The activation energy of motion is 1·2 ± 0·1 eV. Dielectric losses are dominated by the d.c. conductivity, which has an activation energy of 1·16 eV. The hypothesis that the primary charge carrier may be the interstitial fluorine ion is discussed.