X-Ray Diffraction Study on Glass Transition in K_1-x(NH₄)_xI Mixed Crystal

Abstract

X-ray diffraction study on K_1-x(NH₄)_xI mixed crystal with x=0.5 has been carried out to determine the order parameter in the glassy phase. Deviation of the lattice parameter from the Debye approximation was seen in the glassy phase where the diffuse scattering was observed at the (500) reciprocal lattice point. Both the deviation of lattice parameter and the intensity of diffuse scattering increased with decreasing temperature. The results indicate that there is a local distortion which breaks the fcc symmetry in the glassy phase.