0000000000726521
AUTHOR
H. Mutka
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…
Magnetic excitations in an exchange-coupled tetramer cluster of cobalt (II): a study by inelastic neutron scattering
Abstract The polyoxometalate K 10 [Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ].20H 2 O contains a ferromagnetically exchange-coupled tetramer of Co 11 encapsulated in between two diamagnetic molecules (PW 9 O 34 -9 . At 2.5K several inelastic peaks are observed in the energy range 1.5–7 meV, which are assigned to magnetic excitations in the cluster. A tentative interpretation of these data from an anisotropic exchange model yields a cobalt-cobalt interaction of 3meV (24cm -1 ) and an amount of anisotropy J xy / J z ≌0.6. These values are consistent with the magnetic susceptibility measurements.