Muon Site Estimations by DFT Calculations in Metal and Insulating Systems

A way to estimate muon sites in materials is reported. Since the muon has a positive charge, one easiest and conventional way to estimate muon positions is to calculate minimum potential positions. We applied our developed method to estimate those potential minimum positions to some systems which have been studied by mons at the RIKEN-RAL Muon Facility and showed well defined muon-spin precession behavior in magnetically ordered states. Tentative calculation results by using the density functional theory are reported.

Possible Existence of the Stripe Correlations in Electron-Doped Superconducting Cuprates Eu1.85Ce0.15Cu1-yNiyO4+α-δ Studied by Muon-Spin-Relaxation

Partially Ni-substituted electron-doped superconducting cuprates of Eu1.85Ce0.15Cu1-yNiyO4+α-δ (ECCNO) with y = 0, 0.01, 0.02 and 0.05 have been studied by muon-spin-relaxation (mSR) measurements, in order to elucidate whether or not the dynamical stripe correlations of spins and charges exist in electron-doped cuprates. It has been found that the development of the Cu-spin correlation is induced at low temperatures through the Ni substitution and that, for y = 0.02, a muon-spin precession due to a long-range magnetic order has been observed at 10 K. These results suggest a possibility that the stripe model can globally explain the high-Tc superconductivity in both hole- and electron-doped cuprates.