The magnetic hyperfine fields of Cd guest atoms in nickel were measured by perturbed angular correlation spectroscopy with an unprecedented precision. The experiments exhibited the well-known oscillations which were attributed to the substitutional and the cubic C-site of Cd in nickel, but also showed the existence of previously unknown sites through the observation of combined interactions between magnetic hyperfine fields and electric field gradients. The contributions of a large number of possible sites in connection with the properties of the combined interactions were proposed to be responsible for the invisibility of sites as well as for the large amplitudes of some measured frequencies. Following the systematic of magnetic fields of vacancy-associated 5sp-elements in nickel, the measured fields were consistent with theoretical expectations which used the number of vacancies as the primary parameter.

Magnetism of Isolated Cadmium Atoms in Vacancy-Associated Sites in Nickel. W.D.Zeitz, R.Dogra, A.P.Byrne, S.K.Shrestha, A.V.J.Edge, H.Timmers: Physical Review B, 2008, 78[1], 014406 (7pp)