Magnetic hyperfine field at Nd sites in NdAg studied by perturbed angular correlation spectroscopy and ab-initio calculations

The magnetic hyperfine field (BhfBhf) at Nd sites in NdAg was investigated experimentally by perturbed gamma–gamma angular correlation technique using 140La–140Ce probe nuclei and by first-principles electronic structure calculations. The temperature dependence of the observed BhfBhf shows a sharp deviation from an expected Brillouin-like behavior. This behavior is believed to result from an additional magnetic interaction from the polarization of Ce spin moments induced by an exchange interaction between Ce and Nd ions. The experimental results for the temperature dependence of BhfBhf have been fitted by using a model based on the molecular field theory. The results are discussed in terms of a competition between the RKKY interaction and the 5d–5d interaction for the indirect magnetic coupling between the magnetic Nd ions.