EFFECT OF SMALL CONCENTRATIONS OF GD SPINS ON THE KNIGHT-SHIFT AND NUCLEAR-SPIN RELAXATION OF AL-27 IN THE HEAVY FERMION SYSTEM CEAL3

The spin-lattice relaxation rate and Knight shift of 27Al at 9.5 kOe in Ce1-xGdxAl3 with x≤0.02 are reported. The relaxation rate and Knight shift of several samples were investigated over the range 1.5-4.2 K and the Knight shift measurements of the x = 0 sample covered 1.5-300 K. The low temperature relaxation rates indicate a resonance in the conduction electron density of states at the Fermi energy with an additional contribution from fluctuating Gd spins that is consistent with ESR results. The addition of Gd broadens the NMR absorption line and increases the isotropic part of the Knight shift. The average isotropic Knight shift at the Al sites associated with the Gd moments corresponds to about half the transferred hyperfine field from the Ce sites. © 1990.