Jan Zabloudil

Magnetic properties of single atoms of Fe and Co on Ir(111) and Pt(111)

In using the fully relativistic versions of the embedded cluster and screened Korringa-Kohn-Rostoker methods for semi-infinite systems the magnetic properties of single adatoms of Fe and Co on Ir(111) and Pt(111) are studied. It is found that for Pt(111) Fe and Co adatoms are strongly perpendicularly oriented, while on Ir(111) the orientation of the magnetization is only out of plane for a Co adatom; for an Fe adatom it is in plane. For comparison, the so-called band energy parts of the anisotropy energy of a single layer of Fe and Co on these two substrates are also shown. The obtained results are compared to recent experimental studies using, e.g., the spin-polarized STM technique.

Total-energy calculations with the full-potential KKR method

Abstract We present total-energy calculations for Al, Ni, Fe and Cu based on the full-potential (FP) Korringa-Kohn-Rostoker (KKR) Green-function (GF) method. We show that calculated lattice constants and bulk moduli are in excellent agreement with the values obtained by other FP methods. We focus on the difference between the local-spin-density and generalized-gradient approximations (LSDA and GGA) and show that GGA values for lattice constants and bulk moduli agree very well with experiment. We also discuss some technical details concerning the numerical accuracy of the FP-KKR-GF method.

Concentration dependent spin-flip energies for alloyed surface magnets

Abstract Single and double spin-flip energies are calculated for n layers of homogeneously disordered Fe c Co1-c on Cu(100) with n varying between three and six. It is found that these spin-flip energies describe quite accurately the type of most favourable magnetic coupling between the magnetic layers and also give a rather detailed picture for the occurrence of certain magnetic configurations. A phase diagram of ferromagnetic versus antiferromagnetic coupling with respect to the number of layers and Fe concentration turns out to be closely related to the phase diagram of the reorientation transition in this system.

Layer- and component-resolved magnetic moments and anisotropy energies in (FexCo1- x)n/Cu(100)

Abstract The magnetic moments in the (Fe x Co1-x ) n /Cu(100) system are calculated and shown for 2 ≤ n ≤ 7 and x =0.9 as resolved with respect to layers and components. While, as reported previously, in the ground state antiferromagnetic interlayer coupling between buried Fe layers occurs, surprisingly, also antiferromagnetic Co-Co and Fe-Co interlayer coupling is found. However, by assuming only ferromagnetic nearest-neighbour Fe-Co and Co-Co interactions on top of the dominating antiferromagnetic Fe-Fe nearestneighbour interactions, it is revealed that a simple Ising model is consistent with the results of the selfconsistent calculations. When analysing also the layer- and component-like band energy contributions to the magnetic anisotropy energy, remarkably different behaviour for the Fe and Co contributions can be seen.

On the reorientation transition in Cu(100)/Nin/H

Using the results of a previous study in terms of the scalar-relativistic full- potential linearized augmented-plane-wave method, the fully relativistic screened Korringa-Kohn-Rostoker approach is applied in order to describe the shift in the critical thickness for the so-called inverse reorientation transition from in plane to perpendicular in Ni films on Cu(100) upon loading with H. It is argued that, on average, by loading with H the interlayer distances in the Ni films would have to be reduced by about 3% or, expressed in absolute distances by about 0.05 A, compared with the bare systems, to cause the critical thickness to decrease from about 10 monolayers (ML) for the bare systems to about 8ML for completely H-covered Ni films. Calculations with statistically partial coverages with H and for a complete diffusion of H in the first Ni layer convincingly support this view.