0000000000496623
AUTHOR
B. Lüthi
LaAg x In1?x
The phonon dispersion of LaAg x In1−x (x=1, 0.89, 0.8) has been studied by inelastic neutron scattering in the cubic high temperature phase. A soft mode behaviour was observed at theM-point. The doubling and the cubic to tetragonal deformation of the elementary cell was observed through the phase transition. The measurements of the elastic constants were extended to 450 K and their magnetic field dependence was investigated.
Singlet ground state magnetism: II. magnetic excitons in paramagnetic TbP
The magneticΓ 1 –Γ 4 exciton of the singlet ground state system TbP has been studied by inelastic neutron scattering above the antiferromagnetic ordering temperature. Considerable dispersion and a pronounced splitting was found in the [100] and [110] directions. Both the band width and the splitting increased rapidly as the transition temperature was approached in accordance with the predictions of the RPA-theory. The dispersion is analysed in terms of a phenomenological model using interactions up to the fourth nearest neighbour.
Magnetic resonances in low-dimensional spin systems
Abstract We present magnetic resonance experiments in the frequency range of 35 to 460 GHz at low temperatures (1.5 K) for the two compounds CsNiCl 3 and (CH 3 ) 4 NMnCl 3 (TMMC). In both cases the large frequency range enables us to make a precise determination of the various coupling constants (exchange interactions and anisotropy parameters). For CsNiCl 3 we found a larger interchain exchange than previously determined. These constants can then be used for a critical evaluation of other related experiments. In TMMC we found resonances which cannot be explained by existing models.