AN OVERALL ENERGY-SPECTRUM OF MAGNETIC FLUCTUATIONS IN THE SUPERCONDUCTING LA1.85SR0.15CUO4

High-energy pulsed neutron inelastic scattering experiments have been performed using single crystals of La1.85Sr0.15CuO4 to study magnetic fluctuations in the superconducting phase. A peak centered at the reci procal point (pi, pi) is well defined below around 120 meV and rapidly damped beyond this energy. However, the ''background-subtracted'' sca ttering intensities indicate that magnetic signals remain up to around 300 meV. These data combined with the results obtained by triple-axis neutron scattering experiments provide the first overall energy spect rum of the dynamical susceptibility in La-1.85 Sr(0.15)Cuo(4). The obt ained spectrum is much wider than that of YBa2Cu3O7-d(d similar to 0).