Spin dynamics of the spin ladder system Sr14Cu24O41

Detailed inelastic neutron scattering studies of the spin dynamics in the s pin ladder system Sr14Cu24O41 has been performed. We confirm the existence of a spin gap in the ladders as reported earlier in NMR and pulsed neutron work on polycrystalline samples. Using large single crystals, we studied se parately the spin excitations of the chain and the ladder subsystems. For t he ladders, we clearly show that the inter-ladder coupling is extremely wea k and the dispersion relation of the spin dynamics is essentially quasi-ID and remarkably steep. (C) 1999 Elsevier Science B.V. All rights reserved.