Dipolar and quadrupolar freezing in (NaCN)1−x(KCN)x

Elastic and quasielastic neutron scattering studies in KBr:KCN mixed crystals

Neutron scattering studies in (KBr)1–x(KCN)x mixed crystals are presented utilizing powder diffraction, single crystal diffraction and time-of-flight techniques. Forx>0.6 (KBr)1–x(KCN)x crystals exhibit ferroelastic and ferroelectric low-temperature phases. Crystals withx<0.6 undergo transitions into an orientational glass state. Here we present a detailed phase diagram including new results for x=0.85 and x=0.65. For the latter system a stable rhombohedral low-temperature phase has been detected where the orientational disorder of the plastic phase is only partly removed and quadrupolar relaxations between three body diagonals are still possible. From the powder diffraction experimen…

Phases and phase transitions in the mixed molecular system (NaCN)1x(KCN)x

The phase diagram of (NaCN)1−x(KCN)x was examined by neutron powder diffraction in the temperature range 5K ≦T≦300 K. Several non-cubic low-temperature phases were identified for concentrationsx<xc1=0.15 andx≧xc2=0.89. Lattice parameters and ferroelastic deformations were determined from the observed powder patterns. The phase transformations were characterized following the temperature dependence of the appropriate order parameters.

Neutron powder diffraction study in the mixed molecular system (NaCN)1−x(KCN)x

A detailed structural analysis of (NaCN${)}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$(KCN${)}_{\mathrm{x}}$ mixed crystals with x=0.02, 0.19, and 0.95 was performed by neutron powder diffraction. The structural parameters of the cubic phases were refined, applying a model of preferred orientations. Different noncubic low-temperature phases were observed for x=0.02 and 0.95. For x=0.02 the antiferroelectric ordering of ${\mathrm{CN}}^{\mathrm{\ensuremath{-}}}$ dipoles at low temperatures is accompanied by significant alkali-alkali and alkali-${\mathrm{CN}}^{\mathrm{\ensuremath{-}}}$ sublattice shifts. Structural data are presented together with previous results for mixed crystals with x=0.59 and…