Neutron Scattering Study of the Field-Induced Soliton Lattice in CuGeO₃

CuGeO₃ undergoes a transition from a spin-Peierls phase to an incommensurate phase at a critical field of H_c≈12.5T. In the high-field phase a lattice of solitons forms, with both structural and magnetic components, and these have been studied using neutron scattering techniques. Our results provide direct evidence for a long-ranged magnetic soliton structure which has both staggered and uniform magnetizations with amplitudes that are broadly in accord with theoretical estimates. The magnetic soliton width Γ_m and the field dependence of the incommensurability δk_SP are found to agree well with theoretical predictions.