Nuclear Magnetic Resonance in Dilute Alloys of Indium-Lead and Indium-Tin

Abstract

Measurements have been made at 4.2\ifmmode^\circ\else\textdegree\fi{}K of the isotropic Knight shift, the anisotropic Knight shift, and the electric quadrupole coupling of $^{115}\mathrm{In}$ as a function of the solute concentration to 5.8 at.% of Pb in In-Pb and to 9.7 at.% of Sn in In-Sn. The $^{119}\mathrm{Sn}$ isotropic Knight shift was also measured in the range 2.9-9.7 at.% Sn in the In-Sn alloys. A comparison of these results with the scattering theories of Blandin and Daniel and of Kohn and Vosko is made. Qualitative agreement is found in the isotropic Knight shift from 2-6 at.% for both alloy systems. Both systems show a sharp dip in the Knight shift in the 0-2 at.% range that are not attributable to the scattering mechanism. The electric-field-gradient calculations show that the ionic and conduction-electron gradients are both negative. A qualitative test in this model for the Sternheimer antishielding factor is in agreement with the value $1\ensuremath{-}{\ensuremath{\gamma}}_{\ensuremath{\infty}}=25.9$.