In-plane hole density in Ca(0.1)La(0.9)Ba(1.65)La(0.35)Cu(3)O(y) ; nuclear resonance study over the full doping range

We report in-plane Cu(63) Nuclear Magnetic Resonance measurements for a series of fully enriched Ca(0.1)La(0.9)Ba(1.65)La(0.35)Cu(3)O(y) powder samples, which belong to the YBCO family, but the doping could vary from very underdoped to extremely overdoped. From these measurements we determine the average nuclear quadrupole resonance frequency \nu_Q, and its second moment \Delta(\nu_Q), both set by the in-plane hole density, n, as a function of oxygen level, y. We find that in the overdoped side n is saturated, but \Delta(\nu_Q) rapidly increases with increasing y. The relevance of these results to the increasing penetration depth in overdoped cuprates is discussed.