HIGH-ENERGY SPIN EXCITATION OF A HIGH-TC SUPERCONDUCTOR LA1.85SR0.15CUO4

High energy inelastic neutron scattering has been performed on a singl e crystal of La1.85Sr0.15CuO4 (Tc=37K) by using pulse neutron techniqu e. The whole spectrum of the quantum magnetic excitation in the wide r ange of the energy-momentum space has been clearly observed for the fi rst time. The shape of the spectrum is very broad and continuous and t he excitation persists up to 280meV above the well known incommensurat e magnetic excitation around (pi, pi, 0).