Magnetic and superconducting phase diagram of electron-dopedPr1−xLaCexCuO4

We have investigated the magnetism and the superconductivity of the electron-doped ${\mathrm{Pr}}_{1-x}{\mathrm{LaCe}}_x{\mathrm{CuO}}_4$ by means of zero-field muon spin rotation/relaxation and magnetic susceptibility measurements. At low temperatures, a well-defined muon spin rotation free from the effect of rare-earth moments was observed for samples with $x<~0.08$ corresponding to the antiferromagnetic (AF) order of Cu spins. Bulk superconductivity was identified in a wide Ce concentration range of $0.09<~x<~0.20$ with a maximum transition temperature of 26 K. Abrupt appearance of the superconducting (SC) phase at $x\sim 0.09$ is concomitant with a destroy of the AF ordered phase, indicating the competitive relation between two phases. Possible relation between the wide SC phase and the lattice spacing is discussed.