Effect of Paramagnetic Impurities on Nuclear Spin-Lattice Relaxation: A Numerical Study

Abstract

The effect of paramagnetic impurities on the nuclear spin-lattice relaxation time in metals is investigated by applying the theory of Blume and Hubbard in an appropriately generalized form. The calculations are carried out at finite temperature and magnetic field strength assuming that the Ruderman-Kittel-Kasuya-Yosida interaction couples the impurity spins. The effect of approximating this interaction by $\frac{1}{r^3}$ is examined as is the temperature, magnetic field, and impurity-concentration dependence of the relaxation time. Quantitative results are obtained using parameters appropriate to the rare-earth alloy ${\mathrm{La}}_{1-c}{\mathrm{Gd}}_c{\mathrm{Al}}_2$ and a comparison is made with experiment; agreement is generally good.