mSR study of antiferromagnetic fluctuations in the undoped (Ce-free) superconductor T'-La2-zEuzCuO4

This purpose is to investigate the electronic state of the undoped (Ce-free) superconductor Ln2CuO4 (Ln: lanthanide elements) with the Nd2CuO4-type (so-called T'-type) structure. In electron-doped (Ce-doped) high-Tc superconductors of T'-Ln2-xCexCuO4, it has been believed for a long time since the discovery that superconductivity appears at x ≳ 0.14 and an antiferromagnetic (AF) long-range order is developed at x ≲ 0.14. Therefore, the undoped mother compounds T’-Ln2CuO4 have been recognized to be Mott insulators. However, the observation of superconductivity in undoped T’-Ln2CuO4 has raised questions as to the electronic and magnetic states. The change of the AF correlation in T'-La2-zEuzCuO4 is expected to give the significant information of the electronic state.