High-energy spin excitations in the electron-doped superconductor Pr0.88LaCe0.12CuO4-δ with Tc=21 K

We use high-resolution inelastic neutron scattering to study the low-temperature magnetic excitations of the electron-doping superconductor Pr0.88LaCe0.12CuO4-delta (T-c=21 +/- 1 K) over a wide energy range (4 meV <= h omega <= 330 meV). The effect of electron doping is to cause a wave vector (Q) broadening in the low-energy (h omega <= 80 meV) commensurate spin fluctuations at (0.5, 0.5) and to suppress the intensity of spin-wave-like excitations at high energies (h omega >= 100 meV). This leads to a substantial redistribution in the spectrum of the local dynamical spin susceptibility chi('')(omega), and reveals a new energy scale similar to that of the lightly hole-doped YB2Cu3O6.353 (T-c=18 K).