Magnetism and Superconductivity in under-doped region of T*-type La1-x/2Eu1-x/2SrxCuO4-yFy

We propose the muSR measurements on La0.91Eu0.91Sr0.18CuO4-yFy, which has CuO5 pyramid structure with five coordination of Cu ions, to investigate the ground state of the parent compound and the doping evolution of magnetism in T*-type cuprate. After the discovery of superconductivity in parent T’-type RE2CuO4 (RE = Rare earth) without cation substitution, the relationship between Cu coordination and the physical properties of lamellar cuprate oxide have been intensively studied. T*-type cuprate provides a unique opportunity to complement the lack of basic knowledge for this issue. However, no experimental study on magnetism in the under-doped region of T*-type cuprate has been reported. In this study, combined with the magnetic susceptibility measurement and our previous works, we complete the phase diagram for both as-sintere and oxygen annealed samples of T*-type cuprate.