DIMERIZED GROUND-STATE AND MAGNETIC EXCITATIONS IN CACUGE2O6

The S = 1/2 Heisenberg antiferromagnet CaCuGe2O6 was studied by inelas tic neutron scattering on a powder sample in the temperature range 5-3 00 K. A sharp symmetric magnetic inelastic peak was observed around h omega=6 meV, and its q and temperature dependences were investigated. The absolute values of the energy-integrated magnetic intensity were d etermined. Despite the fact that from the structural point of view the material has a distinct one-dimensional arrangement of magnetic sites , the experimental results are surprisingly well described by an ensem ble of weakly interacting antiferromagnetic dimers, which are composed of pairs of Cu2+ ions.