EXAFS studies of KBr1-x(NO2)(x) mixed crystals

EXAFS studies of KBr1-x(NO2)(x) mixed crystals (x < 0.4) were performed to elucidate the local structure of their dipole glass. The local structure, e specially the nearest bromine-potassium pair-distribution, is not affected by replacing bromine ions with nitrite ones even below the glass transition temperature. The mean-square displacement of the bromine-potassium pair-di stribution obeys the Debye approximation, while that of average structure d erived from previous X-ray diffraction studies deviates largely from the ap proximation. The results indicate that a cluster with only short-range ferr oelectric correlation is induced by the short-range order of nitrite ions w ithin the distorted or fluctuated lattice caused by their reorientational f reezing.