The Hyperfine Fields of Gd in Tb–Gd, Dy–Gd, Er–Gd and Tm–Gd Alloys Obtained by NMR Measurements

Abstract

The nuclear magnetic resonances of Gd 155 and Gd 157 in Tb 12% –Gd, Dy 10% –Gd, Er 9% –Gd and Tm 7% –Gd alloys have been studied at 1.4 K by the spin echo method. These experiments have shown the dependence of the magnetic hyperfine field at Gd nuclei upon the angle θ between the crystallographic c -axis and the direction of the magnetic moment of Gd. The magnetic hyperfine fields have been found to be 333 kOe in Tb 12% –Gd with angle θ=90° and 396 kOe in Er 9% –Gd with angle θ=27°. The observed electric field gradients (EFG) were nearly the same in these alloys. The values of the EFG were 2.0×10 24 cm -3 in Tb 12% –Gd and 2.1×10 24 cm -3 in Er 9% –Gd respectively. The contribution of the conduction electrons to the EFG was the same order of magnitude as that of the charges of the ions at every lattice sites.