Nuclear Magnetic Resonance of ¹¹³Cd and ¹⁹⁹Hg in Cd-Mg and Cd-Hg Solid Solutions

The current theoretical and experimental situation with respect to Knight shifts and bulk susceptibility of Cd in pure Cd and in Cd-Mg and Cd-Hg alloys is reviewed. New experimental isotropic and anisotropic Knight shift data on ¹¹³Cd in Cd-Mg and Cd-Hg alloys and on ¹⁹⁹Hg in Cd-Hg alloys are presented. The behavior of the ¹⁹⁹Hg sites is found to be remarkably similar to that of the ¹¹³Cd site in the Cd-Hg alloys. However the ratio of isotropic Knight Shift of ¹⁹⁹Hg to ¹¹³Cd is somewhat greater than the ratio of ¹⁹⁹Hg to ¹¹³Cd atomic hyperfine fields suggesting that there is more local electronic "s" character at the Fermi surface in the alloy than in the pure metals. This is consistent with the theoretical picture of Cd in which phonon scattering induced by increasing temperature or alloying smears and weakens the lattice potential which in turn leads to a more "s" like Fermi surface. Further, the ¹¹³Cd Knight shift is found to be a useful tool for monitoring the phase segregation that occurs in Cd-Mg due to internal oxidation and for determining the concentrations of solutes such as Hg and Mg in Cd-Hg and Cd-Mg alloys.