Investigation of the Magnetic Hyperfine Field at 140Ce on Gd Sites in GdCo2 Compound

Perturbed angular correlation experiments on ¹⁴⁰La–¹⁴⁰Ce probes substituting for the Gd positions on GdCo2 demonstrate that the magnetic hyperfine field (MHF) on Ce atoms follows an expected Brillouin function but with a substantially reduced saturation value as compared with the MHF acting on free Ce⁺³ ions. The results were interpreted with the aid of first principles electronic structure calculations showing that the reduced value of the MHF is a consequence of a small orbital contribution to the MHF which was attributed to the de-localization of the Ce 4f electronic state.