STRUCTURAL-PROPERTIES OF DIPOLAR GLASS-I K1-X(NH4)(X)I

A dipolar glass, K1-x(NH4)(x)I, was examined by a combination of X-ray and neutron diffraction measurements to elucidate structural properti es of its glassy state. The mean structure obtained from X-ray and neu tron structural analyses shows the fluctuation of iodine ions and the short-range order of ammonium ions that locally break the symmetry of the NaCl-type structure. It is proposed that the local distortion of t he lattice is induced by the short-range antiferroelectric order of am monium ions. The local structure deduced appears the coupling model be tween the orientation of ammonium ions and the phonon-like local mode induced by the short-range order of ammonium ions.