Abstract
We report spin-spin and spin-lattice relaxation rates and and magnetic hyperfine shift in the normal state of an optimally doped single-crystalline sample with K (which corresponds to the maximal for the family). The comparison between and evidences that the spin pseudogap does not open above at optimal doping, although the static spin susceptibility starts to decrease well above at K. Comparing the NMR data of this optimally doped sample with those of two other “90 K” samples previously studied by our group, an underdoped and an overdoped strongly suggests that the crossover to the spin pseudogap regime occurs precisely at the optimal doping level. A phenomenological phase diagram based on the NMR results in the normal states is proposed. We discuss to which extent our data agree with the predictions of the magnetic scaling theory.
- Received 3 March 1997
DOI:https://doi.org/10.1103/PhysRevB.56.11294
©1997 American Physical Society