mSR study of antiferromagnetic fluctuations in the hole-doped superconductor T’-La1.8-xEu0.2SrxCuO4

The purpose of this mSR study is to investigate antiferromagnetic (AF) fluctuations in the hole-doped high-Tc cuprate La1.8-xEu0.2SrxCuO4 with the Nd2CuO4-type (so-called T'-type) structure. In the undoped (Ce-free) superconductor T'-Ln2CuO4 (Ln: lanthanide elements), the superconductivity emerges even in the undoped mother compound. Recently, since we have successfully synthesized the electron-doped T'-La1.8Eu0.2CuO4-yFy samples, the hole- and electron-concentration dependence of critical temperature, Tc, for T'-La1.8-xEu0.2SrxCuO4-yFy has been revealed. From our resent mSR measurements of electron-doped T'-La1.8Eu0.2CuO4-yFy, it is found that AF fluctuations disappears at y > 0.10. Therefore, AF fluctuations in hole-doped region would be clarified, leading to the understanding of the relation between the superconductivity and antiferromagnetism in undoped superconductors.