Study of hyperfine interactions in GdIn3

Abstract

In the present work, an experimental and theoretical study of the hyperfine interactions at Gd and In sites in GdIn3 were performed. The experimental measurements were carried out by perturbed angular correlation spectroscopy using 140Ce and 111Cd nuclear probes substituting Gd and In sites, respectively. Results for 111Cd probe at In sites in GdIn3 revealed only electric quadrupole interactions, differently from the results for CeIn3 where, in addition to quadrupole interactions, a magnetic hyperfine field (Bhf) was also observed at In sites. The temperature dependence of Bhf at 140Ce on Gd sites in GdIn3 could be fitted by a Brillouin curve, and the extrapolated Bhf value to 0 K was found to be much smaller than that at 140Ce in CeIn3. Ab-initio electronic structure calculations for GdIn3 matrix doped with Ce were confronted with experimental data in order to explain such differences. The calculations were carried out within density functional theory using Augmented Plane Waves plus local orbitals basis functions as embodied in the wien2k package and with the GGA + U approximation. The value for the Hubbard U parameter was determined for each case. Results of the calculations show that the absence of Bhf in Cd probes in GdIn3 is related with the orientation of the magnetic moments in (001) direction, whereas in CeIn3 the magnetic moments are oriented out of this direction.