Korringa Constant Research Articles

Many-Electron Effects on the Enhancements of the Korringa Constants and Spin-Lattice Relaxation Rates in Alkali Metals

A quantitative explanation of the observed enhancements of the Korringa product and the ratio of Zeeman to dipolar spin-lattice relaxation times in sodium is given. The explanation is based on an extension of the theories of Moriya and Wolff, using for the generalized paramagnetic susceptibility the expression given by the self-consistent theory of Singwi et al. of spin correlations in a low-density interacting electron gas. The theory also predicts that the Korringa constant in the alkali metals is almost constant - a result in agreement with experiment.

Pseudopotential Calculation of the Knight Shift and Relaxation Time in Magnesium

A nonlocal pseudopotential procedure has been utilized to obtain the conduction electron wave functions in magnesium metal. It is found that the use of these wave functions along with a finer scanning of the Fermi surface, namely, 110 points in $\frac{1}{24}$ of the Brillouin zone, leads to a value for the Knight shift ${K}_{s}$ in much better agreement with experiment than was an earlier value obtained by the orthogonalized-plane-wave procedure. Possible sources for the difference in theoretical ${K}_{s}$ values obtained by using these two different procedures are discussed. Improved values of the relaxation time ${T}_{1}$ and Korringa constant are also presented.