Taming the magnetic anisotropy of lanthanides through coordination environments is crucial to take advantage of the lanthanides properties in thermally robust nanomaterials. In this work, the electronic and magnetic properties of Dy‐carboxylate metal–organic networks on Cu(111) based on an eightfold coordination between Dy and ditopic linkers are inspected. This surface science study based on scanning probe microscopy and X‐ray magnetic circular dichroism, complemented with density functional theory and multiplet calculations, reveals that the magnetic anisotropy landscape of the system is complex. Surface‐supported metal–organic coordination is able to induce a change in the orientation of the easy magnetization axis of the Dy coordinative centers as compared to isolated Dy atoms and Dy clusters, and significantly increases the magnetic anisotropy. Surprisingly, Dy atoms coordinated in the metallosupramolecular networks display a nearly in‐plane easy magnetization axis despite the out‐of‐plane symmetry axis of the coordinative molecular lattice. Multiplet calculations highlight the decisive role of the metal–organic coordination, revealing that the tilted orientation is the result of a very delicate balance between the interaction of Dy with O atoms and the precise geometry of the crystal field. This study opens new avenues to tailor the magnetic anisotropy and magnetic moments of lanthanide elements on surfaces.
Equilibria between polyazacycloalkanes of the series [3k]aneN, (k = 3-1 1 ) and the bivalent metal ions of Mn through Zn have been studied. The stability constants (log K) for the complexes of Mn2+,
We demonstrate for the first time that seeded harmonic generation on electron storage rings can produce coherent optical pulses in the vacuum ultraviolet spectral range. The experiment is performed at Elettra, where coherent pulses are generated at 132 nm, with a duration of about 100 fs. The light source has a repetition rate of 1 kHz and adjustable polarization; it is very bright, with a peak power several orders of magnitude above that of spontaneous synchrotron radiation. Owing to high stability, the source is used in a test photoemission electron microscopy experiment. We anticipate that seeded harmonic generation on storage rings can lead to unprecedented developments in time-resolved femtosecond spectroscopy and microscopy.
International audienceWe investigate the chemical and morphological structure of the Au nanodots on Ge(111) which serve as catalysts for the formation of epitaxial Ge nanowires. The spatial localization of Au is investigated by X-ray spectromicroscopy and transmission electron microscopy. We show that dewetting of an Au film on Ge(111) gives rise to a thin Au-Ge wetting layer and Au-Ge dots. These dots are crystallized but not with a single crystallographic orientation. Thanks to the spatially resolved X-ray and transmission electron microscopy measurements, a chemical characterization of both binary Au-Ge catalysts and wetting layer is obtained at the nanoscale. We show that Ge vertical growth is achieved even without external Ge supply
A method for producing self‐organised arrays of nanometric metallic dots is reported. It consists on developing first the nanodot pattern by ion erosion on a semiconductor cover film and transferring it to a previously buried metallic layer. This procedure has been applied to Co, and the ferromagnetic behaviour of the dots at room temperature is demonstrated.
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