Cooperative Study by Neutron Scattering and NMR on Low Dimensional Quantum Spin System

Abstract

We report the results of neutron scattering and nuclear magnetic resonance (NMR) measurements on the two-dimensional quantum spin system SrCu₂(B0₃)₂. The dispersion curve of the first excited state obtained by inelastic neutron scattering is almost flat. The Cu-NMR spectrum splits into four lines by the nuclear spin-spin coupling mediated by the electron spins of Cu ions which form dimers. These results are evidences of the characteristics suggested by theoretical studies. The Cu spectrum at 27.6, where the 1/8 plateau is observed in the magnetization curve, has a large number of peaks distributed over a wide frequency range. By comparing the NMR and theoretical results, the spin structure of the 1/8 plateau phase is determined. These results are good examples of the cooperative study by neutron scattering and NMR.