INVESTIGADORES
TAYLOR Marcela Andrea
artículos
Título:
Electric field gradients of CeMIn5(M=Co, Rh, Ir) heavy-fermion systems studied by perturbed angular correlations and ab initio electronic structure calculations
Autor/es:
M. FORKER; P. R. J. SILVA; J. T. P. D. CAVALCANTE; F. H. M. CAVALCANTE; S. M. RAMOS; H. SAITOVITCH; E. BAGGIO-SAITOVITCH,; R. E. ALONSO; M.A. TAYLOR; L. A. ERRICO
Revista:
PHYSICAL REVIEW B
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2013 vol. 87 p. 1 - 11
ISSN:
1098-0121
Resumen:
The electric field
gradient (EFG) at the highly dilute nuclear probe 111Cd in the heavy fermion
systems CeMIn5, M = Co, Rh, and Ir and YCoIn5 has been
investigated by perturbed angular correlation (PAC) measurements of the nuclear
electric quadrupole interaction (QI) of 111Cd on In sites. Pure and Sn-doped
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 QIs have been observed,
among them a large fraction of 111Cd in unreacted In metal. Detailed
calculations of the EFG at In nuclei and at Cd probes on In sites of pure and
Sn-doped CeMIn5 were preformed, using the full-potential augmented plane
wave+local orbital (APW+lo) formalism and taking into account different
variables such as the electronic structure of the hyperfine probes, probe
induced structural distortions, and impurity doping. The excellent agreement
between the predicted EFGs and the experimental results allows us to
assign two of the observed EFG components to the lattice sites 1c and 4i
of the CeMIn5 compounds and to explain the pronounced difference of
the EFG at In and Cd probes on the same lattice position. Structural
distortions induced by the Cd probe and Sn-doping were found to have little
effect on the EFG at the Cd probes. We also show that the local spin density
approximation (LSDA) and LDA+U calculations predict very similar
equilibrium structures and EFGs at the In/Cd sites. The extension of the
experiments and the calculations from CeMIn5 to YCoIn5 and LaCoIn5 have
established that the influence of the 4f electrons on the EFGs at impurity
sites is negligibly small.