7,776 research outputs found
Induced magnetism at the interfaces of a Fe/V superlattice investigated by resonant magnetic x-ray scattering
The induced magnetic moments in the V 3d electronic states of interface
atomic layers in a Fe(6ML)/V(7ML) superlattice was investigated by x-ray
resonant magnetic scattering. The first V atomic layer next to Fe was found to
be strongly antiferromagnetically polarized relatively to Fe and the magnetic
moments of the next few atomic layers in the interior V region decay
exponentially with increasing distance from the interface, while the magnetic
moments of the Fe atomic layers largely remain bulk-like. The induced V moments
decay more rapidly as observed by x-ray magnetic scattering than in standard
x-ray magnetic circular dichroism. The theoretical description of the induced
magnetic atomic layer profile in V was found to strongly rely on the interface
roughness within the superlattice period. These results provide new insight
into interface magnetism by taking advantage of the enhanced depth sensitivity
to the magnetic profile over a certain resonant energy bandwidth in the
vicinity of the Bragg angles.Comment: 7 pages, 6 figure
Electronic correlation effects in the Cr2GeC Mn+1AXn phase
The magnetic properties, electronic band structure and Fermi surfaces of the
hexagonal Cr2GeC system have been studied by means of both generalized gradient
approximation (GGA) and the +U corrected method (GGA+U). The effective U value
has been computed within the augmented plane-wave theoretical scheme by
following the constrained density functional theory formalism of Anisimov et
al. [1991 Phys. Rev. B 45, 7570]. On the basis of our GGA+U calculations, a
compensated anti-ferromagnetic spin ordering of Cr atoms has been found to be
the ground state solution for this material, where a Ge-mediated super-exchange
coupling is responsible for an opposite spin distribution between the ABA
stacked in-plane Cr-C networks. Structural properties have also been tested and
found to be in good agreement with the available experimental data. Topological
analysis of Fermi surfaces have been used to qualitatively address the
electronic transport properties of Cr2GeC and found an important asymmetrical
carrier-type distribution within the hexagonal crystal lattice. We conclude
that an appropriate description of the strongly correlated Cr-d electrons is an
essential issue for interpreting the material properties of this unusual
Cr-based MAX-phase.Comment: 13 pages, 10 picture
The importance of poverty early in childhood
Introduction: Using a poverty line set at 60% of New Zealand’s median national income, nearly one in five New Zealand children (19%) was poor in 2011. This poverty rate is considerably less than that of the United States and Canada, similar to that of Australia, the United Kingdom, Germany and France, and much greater that in Scandinavian countries. These rates are far from immutable; New Zealand’s child poverty rate was much higher in 2004 before social policies were enacted which focused, in part, on the country’s child poverty problem
Energy Dependence of Cu L2,3 Satellites using Synchrotron Excited X-ray Emission Spectroscopy
The L2,3 X-ray emission of Cu metal has been measured using monochromatic
synchrotron radiation. The self-absorption effect in the spectra is shown to be
very small in our experimental geometry. From the quantitative analysis of
spectra recorded at different excitation energies, the L3/L2 emission intensity
ratio and the partial Auger-width are extracted. High-energy satellite features
on the L3 emission line are separated by a subtraction procedure. The satellite
intensity is found to be slowly increasing for excitation energies between the
L3, L2 and L1 core-level thresholds due to shake-up and shake-off transitions.
As the excitation energy passes the L2 threshold, a step of rapidly increasing
satellite intensity of the L3 emission is found due to additional Coster-Kronig
processes.Comment: 8 pages, 3 figures, http://link.aps.org/doi/10.1103/PhysRevB.56.1223
A Checklist of Illinois Centipedes (Chilopoda): Supplement
(excerpt)
Order SCOLOPENDROMORPHA Family CRYFTOPIDAE Subfamily CRYFTOPINAE
Cryptops hyalinus Say 1821. (Fig. 2). B (Cook; Auerbach [1951]), C (Champaign) F (Hardin, Jackson, Johnson, Pope, Saline, Williamson), G (Jackson, Jefferson, Perry, Williamson),
H (Clark), I (Randolph, Union), J (Alexander)
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