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, especially 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-distribution obeys the Debye approximation, while that of average structure derived from previous X-ray diffraction studies deviates largely from the approximation. The results indicate that a cluster with only short-range ferroelectric correlation is induced by the short-range order of nitrite ions within the distorted or fluctuated lattice caused by their reorientational freezing.