Planar CuO2 hole density in high-Tc cuprates determined by NMR Knight shift: 63Cu NMR on bilayered Ba2CaCu2O4(F,O)2 and three-layered Ba2Ca2Cu3O6(F,O)2

We report that planar CuO2 hole densities in high-T-c cuprates are consistently determined by the Cu NMR Knight shift. In single-and bilayered cuprates, it is demonstrated that the spin part of the Knight shift K-s(300 K) at room temperature monotonically increases with the hole density p from the underdoped to overdoped regions, suggesting that the relationship of K-s (300 K) vs p is a reliable measure to determine p. The validity of this K-s(300 K)-p relationship is confirmed by the investigation of the p dependencies of hyperfine magnetic fields and of spin susceptibility for single-and bilayered cuprates with tetragonal symmetry. Moreover, the analyses are compared with NMR data on three-layered Ba2Ca2Cu3O6(F,O)(2) and HgBa2Ca2Cu3O8+delta and five-layered HgBa2Ca4Cu5O12+delta, which suggests the general applicability of the K-s(300 K)-p relationship to multilayered compounds with more than three CuO2 planes. The measurement of K-s(300 K) enables us to separately estimate p for each CuO2 plane in multilayered compounds, where doped hole carriers are inequivalent between outer CuO2 planes and inner CuO2 planes.