Electric field gradients of CeMIn5 (M: Co, Rh, Ir) heavy fermion systems studied by perturbed angular correlations and ab-initio electronic structure calculations

M. FORKER; P.R.J. SILVA; J.T.P.D. CAVALCANTE; F.H.M. CAVALCANTE1; S.M. RAMOS; H. SAITOVITCH; E. BAGGIO-SAITOVITCH; R. E. ALONSO; M. A. TAYLOR; L. A. ERRICO

JOURNAL OF PHYSICS CONDENSED MATTER

IOP PUBLISHING LTD

Lugar: Londres; Año: 2012

0953-8984

Trabajo enviado a Journal of Physics Condensed Matter en Diciembre de 2012. Finalmente aceptado para su publicacion en Physical Review B en Marzo de 2013. The nuclear electric quadrupole interaction (QI) of the nuclear probe 111In-111Cd in the heavy fermion systems CeMIn5, M = Co, Rh and Ir and YCoIn5 has been investigated by perturbed angular correlation (PAC) spectroscopy. Single crystals prepared by In-flux synthesis and polycrystalline samples prepared by arc melting have been studied. The samples were doped with the PAC probe 111Cd by diffusion of the mother isotope 111In.  In all samples, several fractions of 111Cd probe nuclei subject to different QI´s have been observed. Detailed calculations of the electric field gradient (EFG) at In and Cd nuclei in pure and Cd-doped CeMIn5 using the full-potential augmented plane wave+local orbital (APW+lo) formalism allowed us to assign two of the observed EFG fractions to the 1c and 4i lattice sites in the CeMIn5 compounds. The extension of the experiments and calculations from CeMIn5 to YCoIn5 and LaCoIn5 has established that the influence of the 4f electrons on the EFGs at impurity sites is negligibly small. The effects of different variables (electronic structure of the hyperfine probes, structural distortions induced by the Cd impurity, the effect of Sn doping) were investigated in detail and are compared with experimental results reported in the literature.