Spin correlations in electron-doped high-T_c superconductor

Spin correlations in the electron-doped Pr_{1 - x} LaCe_x CuO₄ have been investigated by neutron-scattering and muon rotation/relaxation measurements. The low-enegy spin correlations were found to be in commensurate with the wide superconducting phase, unlike the incommensurate ones in the hole-doped La_{2 - x} Sr_x CuO₄. No enhancement of the magnetic order by impurity-doping and applying magnetic fields was observed, although the superconductivity is effectively suppressed, compared to that in the hole-doped system. Distinct impurity and magnetic field effects between the static spin correlation in the electron-doped system and those in the hole-doped systems suggest the different magnetic ground state in the two systems.