Dimerized ground state and magnetic excitations inCaCuGe2O6

The S=1/2 Heisenberg antiferromagnet ${\mathrm{CaCuGe}}_2$ ${\mathrm{O}}_6$ was studied by inelastic neutron scattering on a powder sample in the temperature range 5–300 K. A sharp symmetric magnetic inelastic peak was observed around ħω=6 meV, and its q and temperature dependences were investigated. The absolute values of the energy-integrated magnetic intensity were determined. 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 ensemble of weakly interacting antiferromagnetic dimers, which are composed of pairs of ${\mathrm{Cu}}^{2+}$ ions. © 1996 The American Physical Society.