抄録
Extended X-ray absorption fine structure (EXAFS) studies are carried out for fluorites, β-PbF2 (at 80 K, 293 K and 640 K) and SrF2 (at 293 K and 640 K) to investigate their ion conduction mechanism of anion. In β-PbF2 it is found that fluorine ion does not occupy only the center of the Pb tetrahedron site but displaces along ⟨111⟩ into several separate sites even at 80 K and this tendency is remarkably increased as temperature increased up to its transition temperature. In SrF2 it is found that fluorine ion also displaces along ⟨111⟩ but is smaller in quatity at the same temperature as compared with β-PbF2. These interstitial anions play a key role in ion conduction process indicating that hopping model of anion is probable.
