Crystal Structure and Ferromagnetism of the CeFeSi Intermetallic Compound.

We have determined the crystal structure and the magnetic state of the CeFeSi intermetallic compound. Our revised structural model (fully ordered tetragonal unit cell, 4/) agrees with the previous literature report, except for some minor quantitative differences. Magnetically, the CeFeSi undergoes a ferromagnetic transition at the temperature ≈ 94 K.

Revealing the Epitaxial Interface between AlFe and AlFe Enabling Atomic Al Interdiffusion.

Steel is the most commonly manufactured material in the world. Its performances can be improved by hot-dip coating with the low weight aluminum metal. The structure of the Al∥Fe interface, which is known to contain a buffer layer made of complex intermetallic compounds such as AlFe and AlFe, is crucial for the properties.

X-ray photoelectron diffraction study of the approximant AlCo(001) quasicrystal.

The intermetallic AlCo is defined as a structurally complex material and is considered a low-order quasicrystalline approximant. A single crystal of AlCo(001) was obtained by the Czochralski method. The sample was characterized by X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), and X-ray photoelectron diffraction (PED).

Probing spin fluctuations of the quantum phase transition in CeAl by muon spin rotation.

We report on the dynamics of a magnetic-field-driven antiferromagnetic-to-paramagnetic quantum phase transition in monocrystalline CeAl via transverse-field muon spin rotation (TF-µSR) experiments down to low temperature of [Formula: see text] 80 mK. The quantum phase transition is of a spin-flip type and takes place on the Ce-Al magnetic chains as a result of competition between the indirect exchange and the Zeeman interaction of the Ce moments with the external field, applied along the chain direction (also the direction of the antiferromagnetic axis). The Ce moments are not static at [Formula: see text] 0, but fluctuate in their direction due to the Heisenberg uncertainty principle.

Structural Model and Spin-Glass Magnetism of the CeAuGe Quasicrystalline Approximant.

In a search for unconventional heavy-Fermion compounds with the localized 4f moments distributed quasiperiodically instead of a conventional distribution on a regular, translationally periodic lattice, we have successfully synthesized a stable CeAuGe Tsai-type 1/1 quasicrystalline approximant of the off-stoichiometric composition CeAuGe ( = 0.17, = 0.49, = 1.

Pseudo-2-Fold Surface of the AlCo Catalyst: Structure, Stability, and Hydrogen Adsorption.

A few low-order approximants to decagonal quasicrystals have been shown to provide excellent activity and selectivity for the hydrogenation of alkenes and alkynes. It is the case for the AlCo compound, for which the catalytic properties of the pseudo-2-fold orientation have been revealed to be among the best. A combination of surface science studies, including surface X-ray diffraction, and calculations based on density functional theory is used here to derive an atomistic model for the pseudo-2-fold -AlCo surface, whose faceted and columnar structure is found very similar to the one of the 2-fold surface of the -Al-Ni-Co quasicrystal.

Crystalline and Electronic Structures of the AlVSn ( = 0.19) Intermetallic Compound.

A new ternary phase with a composition AlVSn ( = 0.19) has been found during investigation of the Al-V-Sn ternary system. Single-crystal X-ray diffraction measurements reveal that this ternary phase crystallizes with an orthorhombic structure with = 5.

Catalytic properties of AlTM complex intermetallics: influence of the transition metal and the surface orientation on butadiene hydrogenation.

Complex intermetallic compounds such as transition metal (TM) aluminides are promising alternatives to expensive Pd-based catalysts, in particular for the semi-hydrogenation of alkynes or alkadienes. Here, we compare the gas-phase butadiene hydrogenation performances of AlCo(100), -AlFe(010) and -AlRu(010) surfaces, whose bulk terminated structural models exhibit similar cluster-like arrangements. Moreover, the effect of the surface orientation is assessed through a comparison between AlCo(100) and AlCo(010).

A new ternary compound with the BGaIr structure type in the Al-Au-Ir system.

Following the recent determination of the AlAuIr structure, a new ternary phase has been identified in the Al-Au-Ir phase diagram. It has a chemical composition Al(Au;Ir) with an apparently low gold content. Its crystal structure has been determined with single-crystal X-ray diffraction.

Al3AuIr: A New Compound in the Al-Au-Ir System.

A new ternary phase with a composition of Al3AuIr has been found in the Al-rich area of the Al-Au-Ir system. Differential thermal analysis indicates a melting point of 990 °C, and single-crystal X-ray diffraction measurements reveal that this ternary phase adopts a Ni2Al3 structure type (space group P3̅m1) with a = 4.2584(5) Å and c = 5.

Self-organized molecular films with long-range quasiperiodic order.

Self-organized molecular films with long-range quasiperiodic order have been grown by using the complex potential energy landscape of quasicrystalline surfaces as templates. The long-range order arises from a specific subset of quasilattice sites acting as preferred adsorption sites for the molecules, thus enforcing a quasiperiodic structure in the film. These adsorption sites exhibit a local 5-fold symmetry resulting from the cut by the surface plane through the cluster units identified in the bulk solid.