Charge and spin dynamics in the electron-doped high temperature superconducting cuprates

We show that the 63Cu and 17O NMR spin-lattice relaxation rates from the electron-doped high temperature superconducting cuprates (HTSC), Sr0.9La0.1CuO2 and Pr1.85Ce0.15CuO4 are consistent with antiferromagnetic spin fluctuations in the CuO2 planes. However, unlike the hole-doped HTSC, there is no normal-state pseudogap or spin-gap. Furthermore, there is no evidence for a slowing down of the spin dynamics that is observed in underdoped and hole-doped HTSC and attributed to electronic phase separation. We also find that the normal-state static spin susceptibility in Sr0.9La0.1CuO2 is only ∼15% of that observed in the hole-doped HTSC.