Abstract of Publication No. 482
Th. Strässle, F. Juranyi, M. Schneider, S. Janssen, A. Furrer, K. W. Krämer and H. U. Güdel
The origin of higher-order exchange interactions in localized
S-state systems has been the subject of intensive
investigations in the past. In particular, it has been suggested that
a biquadratic exchange term may arise from the magnetoelastic energy.
Here we report on the pressure and temperature dependence of the
excitation spectra of magnetic Mn2+ dimers in
CsMn0.28Mg0.72Br3 probed by inelastic neutron
scattering. Biquadratic exchange and a strong distance dependence of
the bilinear exchange are observed. It is shown that the mechanism
of local exchange striction may explain the occurrence of biquadratic
exchange in accordance with the elastic properties of the compound.