X-RAY-DIFFRACTION STUDY OF KBR1-X(NO2)(X) MIXED-CRYSTAL

An X-ray diffraction study of KBr0.64(NO2)(0.36) was performed to eluc idate its structural glass-like properties and compare them to those o f other mixed crystals. As the temperature decreases, the fundamental Bragg reflections begin to decrease and strong diffused scattering app ears around the Brillouin-zone center of an face centered cubic (fcc) lattice, Gamma-point. The results indicate that the local distortion o f a lattice with only short-range ferroelectric correlation is induced by reorientational freezing of nitrite ions. The correlation length e stimated from the diffused scattering is about 23 Angstrom at 100 K, w hich is much smaller than the coherence length of an X-ray.