Doping-dependent reduction of the Cu nuclear magnetic resonance intensity in the electron-doped superconductors

Cu-63 nuclear magnetic resonance (NMR) measurements on the electron-doped high-temperature superconducting cuprate (HTSC), Sr0.9La0.1CuO2, reveal a systematic and large reduction of the Cu NMR signal for temperatures below similar to 180 K. However, a large reduction is not observed for temperatures as low as 6 K in Pr1.85Ce0.15CuO4 that has a higher number of doped electrons per Cu. The reduction of the Cu NMR intensity arises from a spatially inhomogeneous and sudden slowing down of the electron spin dynamics that has been observed in underdoped and hole-doped HTSCs. Our results suggest a correspondence with the hole-doped HTSCs where a large wipeout of the Cu NMR signal is only observed for less than similar to 0.13 doped carriers per Cu.