Pulsed neutron-scattering study of an entire spin excitations in the electron-doped high-Tc superconductor

We have investigated magnetic excitations of an electron-doped superconductor Pr0.89LaCe0.11CuO4 (Tc = 26 K) using pulsed neutron-scattering over a wide range of energy up to ∼180 meV. Spin fluctuations were found to persist around (π, π) reciprocal position at least up to ∼180 meV. With increasing the energy (ω) below 60 meV, peak-width broadens rapidly, while above this energy the width weakly depends on the energy. On the other hand, the scattering intensity shows a gradual decrease as the ω increase. However, no well-defined magnetic intensity was observed, where the peak-width saturates. The observed spin excitations in Pr0.89LaCe0.11CuO4 is compared with those in the hole-doped system from the viewpoint of dual structure of the spectrum.