We have obtained solid-state ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ NMR spectra of a number of ${}_{}{}^{17}{}_{}{}^{}\mathrm{enriched}$ oxides and high-temperature oxide superconductors, including ${\mathrm{Cu}}_2^{\mathrm{I}}$O, ${\mathrm{Cu}}^{\mathrm{II}}$O, ${\mathrm{KCu}}^{\mathrm{III}}$${\mathrm{O}}_2$, ${\mathrm{Bi}}_2$${\mathrm{O}}_3$, ${\mathrm{Tl}}_2$${\mathrm{O}}_3$, ${\mathrm{La}}_{1.85}$${\mathrm{Sr}}_{0.15}$${\mathrm{CuO}}_4$, ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$, ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{8+\mathrm{x}}$, ${\mathrm{Tl}}_2$${\mathrm{Ba}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{8+\mathrm{x}}$, and ${\mathrm{Ba}}_{0.6}$${\mathrm{K}}_{0.4}$${\mathrm{BiO}}_3$. Spectra of all of the simple diamagnetic oxides contain relatively sharp resonances in a ‘‘diamagnetic’’ region of ∼-200 to +700 ppm (from ${\mathrm{H}}_2$O, International Union of Pure and Applied Chemistry δ scale). ${\mathrm{Cu}}^{\mathrm{II}}$O exhibits a broad resonance centered at ∼4500 ppm.

Spectra of all of the Cu-containing superconductors (at 300 K) contain a relatively broad and highly paramagnetically shifted peak, due to ${\mathrm{CuO}}_2$ planes, at ≊1800 ppm, together with a peak or series of peaks, in a more normal diamagnetic region, ≊100–600 ppm from ${\mathrm{H}}_2$O. ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ also contains a peak at ∼2950 ppm, assigned to the chain [O(4)] sites.

The highly shifted (${\mathrm{CuO}}_2$) features undergo a ≊1000–1300 ppm diamagnetic shift in ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ and ${\mathrm{Tl}}_2$${\mathrm{Ba}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{8+\mathrm{x}}$ upon cooling to 77 K (<$T_c$). These highly shifted features are absent in ${\mathrm{Ba}}_{0.6}$${\mathrm{K}}_{0.4}$${\mathrm{BiO}}_3$, although the resonance in ${\mathrm{Ba}}_{0.6}$${\mathrm{K}}_{0.4}$${\mathrm{BiO}}_3$ is ≊500 ppm paramagnetically shifted from that in the parent compound, ${\mathrm{BaBiO}}_3$. ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ NMR spectra of magnetically aligned samples of ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ yield diagonal elements of the electric-field-gradient tensor (${\chi }_{\mathrm{ii}}$) for the ${\mathrm{CuO}}_2$ plane oxygens, O(2) and O(3), of ±(4.02,-6.46,2.44) and ±(3.95,-6.51,2.56) MHz.

The observed resonance frequencies for both sites ($H_0$∥c) are ≊1900 ppm from ${\mathrm{H}}_2$O. For the ${\mathrm{CuO}}_2$ plane in ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{8+\mathrm{x}}$ (at 300 K) and in ${\mathrm{Tl}}_2$${\mathrm{Ba}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{8+\mathrm{x}}$ (at 77 K) the quadrupole coupling constant ($e^2$qQ/h) is ≊6.4 MHz also. For the column or bridging oxygen [O(1)] in ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$, $e^2$qQ/h∼7.3 MHz and η≊0, at 300 K, the isotropic frequency shift is ∼458 ppm, and the anisotropy of the chemical or Knight shift (Δσ) is ∼657 ppm, with ${\sigma }_{?}$∥c. A similar result is found for the apical oxygen in ${\mathrm{La}}_{1.85}$${\mathrm{Sr}}_{0.15}$${\mathrm{CuO}}_4$, with ${\sigma }_{33}$=${\sigma }_{?}$∼694 ppm and ${\sigma }_{11}$=${\sigma }_{22}$=${\sigma }_{\perp }$∼474 ppm, determined on a magnetically ordered sample. For the chain site in ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ [O(4)], we find ${\chi }_{\mathrm{ii}}$=±(3.38,-10.94,7.56) MHz. Calculations suggest for all sites that $V_{\mathrm{zz}}$ is negative and is aligned along the Cu-O-Cu bond axis. Results on oxygen-depleted ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ show considerable broadening of the plane-site features, consistent with the onset of antiferromagnetic ordering, while the column oxygens [O(1)] are much less affected. Temperature-dependence studies of $T_1$ for O(2,3) in ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ indicate Korringa-type behavior above $T_c$, and the Knight shift predicted is in good accord with that observed.

There is no BCS-type relaxation enhancement just below $T_c$. Overall, our results give a broad basis for the assignment of ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$ NMR resonances in most of the classes of high-temperature superconductors currently being investigated (2:1:4, 1:2:3, ${\mathrm{Bi}}_2$${\mathrm{Cu}}_2$, ${\mathrm{Tl}}_2$${\mathrm{Cu}}_2$, and Cu-free Bi-containing phases) and show considerable similarities in frequency shifts (and their temperature dependence), $T_1$, $e^2$qQ/h values, and spin-echo decay behavior, for the ${\mathrm{CuO}}_2$ planes in each system, and between the (La(Sr)O,SrO,BaO) and (TlO,BiO) planes as well.

• Received 27 March 1989

DOI:https://doi.org/10.1103/PhysRevB.40.6832