O. Šipr

Magnetic moments, exchange coupling, and crossover temperatures of Co clusters on Pt(111) and Au(111)

The influence of cluster size and of cluster–substrate interaction on the magnetic properties of Co clusters of 1–10 atoms on Pt(111) and Au(111) is studied by fully relativistic ab initio calculations. The focus is on systematic trends of the spin and orbital magnetic moments, the exchange coupling, and the crossover temperature. The spin magnetic moments of Co clusters are larger for the Pt substrate than for the Au substrate, while the reverse is true for the orbital magnetic moments. The local magnetic moments of Co atoms generally increase if the number of Co neighbours decreases. The exchange coupling constants Jij depend on the cluster size and on the location of respective atoms. The crossover temperature increases monotonically with cluster size and is larger for clusters on Pt than for clusters on Au.

Trends in the magnetic properties of Fe, Co, and Ni clusters and monolayers on Ir(111), Pt(111), and Au(111)

We present a detailed theoretical investigation on the magnetic properties of small single-layered Fe, Co, and Ni clusters deposited on Ir(111), Pt(111), and Au(111). For this, a fully relativistic ab initio scheme based on density functional theory has been used. We analyze the element, size, and geometry specific variations of the atomic magnetic moments and their mutual exchange interactions as well as the magnetic anisotropy energy in these systems. Our results show that the atomic spin magnetic moments in the Fe and Co clusters decrease almost linearly with increasing coordination number on all three substrates, while the corresponding orbital magnetic moments appear to be much more sensitive to the local atomic environment. The isotropic exchange interaction among the cluster atoms is always very strong for Fe and Co exceeding the values for bulk bcc Fe and hcp Co, whereas the anisotropic Dzyaloshinski-Moriya interaction is, in general, one or two orders of magnitude smaller when compared to the isotropic one. For the magnetic properties of Ni clusters, the magnetic properties can show quite a different behavior, and we find in this case a strong tendency towards noncollinear magnetism.

On the importance of the magnetic dipole term Tz in analyzing X-ray magnetic circular dichroism spectra of clusters

Employing ab initio relativistic impurity Green function calculations to Fe and Co clusters on Ni and Au surfaces, we assess the usability of the X-ray magnetic circular dichroism (XMCD) spin sum rule for studying magnetism of supported transition metal clusters. We demonstrate that neglect of the magnetic dipole term Tz might lead to a completely false estimate of how the spin magnetic moment μspin depends on the cluster size. In particular, this would be the case of CoN clusters on Au(111) and on Pt(111).

Finite-temperature magnetism ofFexPd1−xandCoxPt1−xalloys

The finite-temperature magnetic properties of Fe

Interpretation of polarized Cu K x-ray absorption near-edge-structure spectra of CuO

_x

Magnetocrystalline anisotropy of FePt: A detailed view

Pd

Many-body effects in x-ray absorption and magnetic circular dichroism spectra within the LSDA+DMFT framework

_{1-x}

Electronic structure of silicon nitride

and Co

Influence of temperature on the systematics of magnetic moments of free Fe clusters

_x

Zn K edge and O K edge x-ray absorption spectra of ZnO surfaces: implications for nanorods.

Pt