Measurements of the Cd113 nuclear-spin-lattice relaxation time T1 and Hall effect in crystalline CdO, a degenerate semiconductor, have yielded the contact hyperfine strength of the conduction electrons at the nuclei. The product T1T=168 sec °K, independent of temperature T and frequency ν for T=1.4,4.2, and 77-350 °K, and for ν=2-10 MHz. Taking the carrier concentration N=2.6×1019 cm-3 independent of temperature to within 3% at 4.2, 77, and 300°K, and using an effective electron mass me*=0.2me, we calculate an averaged electron probability density at the nucleus, 〈|φF(0)|2〉=7×1025 cm-3, normalized to unity in an atomic volume. A comparison with 〈|φA(0)|2〉 in an isolated atom is interpreted to show that the Fermi level of the impurity band lies in the host-lattice conduction band. The Hall-effect data support this. The resonance frequency shift predicted from the Korringa relationship, -0.017%, is smaller than the observed shift, -0.031%. This is thought to be due to covalency contributions rather than to electron-electron interactions.
Look, D. C.
(1969). NMR Determination of the Conduction-Electron Hyperfine Interaction in Crystalline CdO. Physical Review, 184 (3), 705-708.