Impurity Effects on the Electronic State in the Undoped (Ce-free) Superconductor T′-La_1.8Eu_0.2CuO₄ Studied by Muon Spin Relaxation

Electron-Doping Effect on Tc in the Undoped (Ce-Free) Superconductor T′-La1.8Eu0.2CuO4 Studied by the Fluorine Substitution for Oxygen

“…As to the mechanism of the superconductivity, d-wave paring mediated by spin fluctuations is suggested from experimental results of the impurity effects, 12,13) SR, 13,14) and NMR 15) in undoped (Ce-free) polycrystalline samples of T'-La 1.8 Eu 0.2 CuO 4 , in which nonmagnetic Eu 3+ with a small ionic radius is partially substituted for nonmagnetic La 3+ with a large ionic one to stabilize the T'-type structure during the reduction annealing. 10) As to the electronic state of the undoped (Ce-free) superconductor, there are two possibilities.…”

Fermi-liquid state in $T$*-type La$_{1-x/2}$Eu$_{1-x/2}$Sr$_x$CuO$_4$ revealed via element substitution effects on magnetism

“…T *-type cuprates have an intermediate crystal structure between the T and T -type cuprates, which contains a CuO 5 pyra-mid in the unit cell. Although studies on the physical properties of T *-type cuprates is limited, Kojima et al reported weak magnetism in T *-type La 2 CuO 4 19 , which is qualitatively similar to that in superconducting (SC) T -type RE 2 CuO 4 [19][20][21] . Thus, T*-type cuprates are a notable system for studying the relationship between physical properties and oxygen coordination.…”