Abstract :
Magnetism in a single crystal CaCu3Ti4O12 has been studied using elastic and inelastic neutron scattering. We have measured the order parameter of the antiferromagnetic phase transition at TN=24.1(1) K. The observed magnetic structure can be consistently described by spins ordered collinearly along the crystallographic [111] direction. A spin wave mode of ω=7.3(4) meV has been observed and compared with a linear spin wave theory.
