From Underdoped to Overdoped Regime in YBa2Cu3O6+x; an NMR Investigation of Single Crystals

We present O-17 and Cu-63 NMR results obtained in three single crystals of YBa2 center dot Cu3O6+x: YBa1.92Sr0.08Cu3O7 (T-c = 89 K) which is overdoped, and YBa1.93Sr0.07Cu3O6.92 (T-c = 91 K) and YBazCu(3)O(6.52) (T-c = 59 K), both of which are underdoped. We show that Cu(2) nuclear spin-lattice relaxation rate (NSLRR), the static spin susceptibility, the NSLRR for O(2,3) site as well as its anisotropy, have completely different temperature dependence according to the regime (overdoped or underdoped). The O(2,3) NSLRR and magnetic hyperfine shift (MHS) data seem to confirm that in the overdoped regime, a Fermi liquid description is correct, while in the underdoped regime, a pseudo-gap in the magnetic excitations always opens well above T e. We also show that both neutron inelastic scattering results and Cu(2) and O(2,3) NSLRR results can be explained using the same; chi ''(q, w).