Nuclear Magnetic Resonance in Aluminum Alloys

Publisher Website
Google Scholar
Abstract
The variation of nuclear magnetic absorption intensity with solute concentration is studied in dilute alloys of aluminum. Wipe-out numbers obtained for Cu, Ag, Mg, Zn, Ga, and Si in Al are, in order, 236, 205, 122, 94, 160, and 199. An interpretation of these results in terms of the pseudopotential theory is attempted with moderate success. A systematic discrepancy is found between theory and experiments; theoretical estimates of wipe-out numbers are about 0.7 of observed values. The same theory applied to the electric field gradient on near neighbors of impurity atoms is found to give poor agreement with reported results of double-resonance experiments. It is suggested that one of the primary sources of these discrepancies is the neglect of the Bloch character of conduction electrons in calculating the screening charge distribution.