Magnetic properties of finite Co chains on Pt(111)

Lazarovits, B.; Szunyogh, L.; Weinberger, P.

doi:10.1103/physrevb.67.024415

Cited by 101 publications

(112 citation statements)

References 28 publications

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“…This can be associated with the anisotropy energy contributions being larger at end of the chains than inside as found for finite Co wires deposited on a Pt(111) surface [21]. It can also be seen in table 2 that the orbital moments oscillate stronger in magnitude and orientation than the spin moments.…”

Section: Finite Co Wire At the Step Edge Of A Pt(111) Surfacementioning

confidence: 58%

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Ab initio study of canted magnetism of finite atomic chains at surfaces

Lazarovits¹,

Újfalussy²,

Szunyogh³

et al. 2004

J. Phys.: Condens. Matter

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Abstract. By using ab initio methods on different levels we study the magnetic ground state of (finite) atomic wires deposited on metallic surfaces. A phenomenological model based on symmetry arguments suggests that the magnetization of a ferromagnetic wire is aligned either normal to the wire and, generally, tilted with respect to the surface normal or parallel to the wire. From a first principles point of view, this simple model can be best related to the socalled magnetic force theorem calculations being often used to explore magnetic anisotropy energies of bulk and surface systems. The second theoretical approach we use to search for the canted magnetic ground state is first principles adiabatic spin dynamics extended to the case of fully relativistic electron scattering. First, for the case of two adjacent Fe atoms an a Cu(111) surface we demonstrate that the reduction of the surface symmetry can indeed lead to canted magnetism. The anisotropy constants and consequently the ground state magnetization direction are very sensitive to the position of the dimer with respect to the surface. We also performed calculations for a seven-atom Co chain placed along a step edge of a Pt(111) surface. As far as the ground state spin orientation is concerned we obtain excellent agreement with experiment. Moreover, the magnetic ground state turns out to be slightly noncollinear.

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Section: Finite Co Wire At the Step Edge Of A Pt(111) Surfacementioning

confidence: 58%

“…It should be noted that, similar to as discussed in Ref. [18], the change of the anisotropy constants, K 2,i with respect to the position of the Fe dimer can be related to the different hybridization between the electronic states of the Fe and the Cu atoms.…”

Section: Two Fe Impurities At Cu(111) Surfacesmentioning

confidence: 94%

Ab initio study of canted magnetism of finite atomic chains at surfaces

Lazarovits¹,

Újfalussy²,

Szunyogh³

et al. 2004

J. Phys.: Condens. Matter

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“…The magnitude of the XMCD effect relative to the total absorption signal also shows that the spin magnetic moment is increased with respect to the bulk value, but its precise determination is made difficult by the uncertainty in the dipolar spin moment that enters in the XMCD spin sum rule [30][31][32][33]. Local spin density calculations using a variety of approximation schemes, however, consistently indicate a Co spin moment between 2.1 and 2.3µ B /atom [32][33][34][35][36][37][38]. These findings and their interpretation in terms of (de)localization of the Co 3d VINDIGNI et al Finite-sized Heisenberg chains and magnetism of one-dimensional metal systems 387 states are discussed in more detail in Refs.…”

Section: Local Magnetic Momentsmentioning

confidence: 99%

Finite-sized Heisenberg chains and magnetism of one-dimensional metal systems

et al. 2005

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We present a combined experimental and theoretical study of the magnetization of one-dimensional atomic cobalt chains deposited on a platinum surface. We discuss the intrinsic magnetization parameters derived by X-ray magnetic circular dichroism measurements and the observation of ferromagnetic order in one dimension in connection with the presence of strong, dimensionality-dependent anisotropy energy barriers of magnetocrystalline origin. An explicit transfer matrix formalism is developed to treat atomic chains of finite length within the anisotropic Heisenberg model. This model allows us to fit the experimental magnetization curves of cobalt monatomic chains, measured parallel to the easy and hard axes, and provides values of the exchange coupling parameter and the magnetic anisotropy energy consistent with those reported in the literature. The analysis of the spin-spin correlation as a function of temperature provides further insight into the tendency to magnetic order in finite-sized one-dimensional systems.

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“…Ab-initio calculations ( Fig. 1) [30,34] show that the atomic coordination rather than the absolute particle size is the key to determine m L and E a (see Fig. 1).…”

Section: Orbital Magnetic Moment and Magnetic Anisotropy Of Single Comentioning

confidence: 99%

“…The values of m L between brackets have been computed within the orbital polarization scheme with a 50% reduced Racah parameter. The reported values have been averaged over all Co sites for a given island, although site differences may well be relevant (see, e.g., [34]). (empty symbols) measured at T = 5.5 K. The points represent the peak of the L 3 XMCD intensity at 778.6 eV divided by the pre-edge intensity at 775 eV as a function of B.…”

Section: Orbital Magnetic Moment and Magnetic Anisotropy Of Single Comentioning

confidence: 99%

Magnetic anisotropy from single atoms to large monodomain islands of Co/Pt(111)

Gambardella

Rusponi

Cren

et al. 2005

Comptes Rendus. Physique

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By studying the magnetic behavior of self-assembled Co islands on a single-crystal metal surface, Pt(111), we show how the magnetic anisotropy evolves from isolated atoms to monolayer islands and films. Single Co adatoms are found to have a giant magnetocrystalline anisotropy energy of E a = 9.3 ± 1.6 meV/atom arising from the combination of partly preserved orbital moments (m L = 1.1 µ B ) and strong spin-orbit coupling induced by the Pt substrate. Combined scanning tunneling microscopy and X-ray magnetic circular dichroism experiments performed for differently sized small two-dimensional Co islands establish a clear connection between E a and m L , both quantities decrease sharply with the lateral coordination of the magnetic atoms. In accordance with this, Kerr magnetometry experiments, again performed in conjunction with scanning tunneling microscopy, reveal that the anisotropy energy of large two-dimensional Co islands is almost entirely determined by the relatively low number of perimeter atoms, having E a = 0.9 ± 0.1 meV/atom. These results confirm theoretical predictions and are of fundamental value the understanding of how the magnetic anisotropy develops in finite-size magnetic particles. Identification of the role of perimeter and surface atoms opens up new opportunities for engineering the anisotropy and the moment of a magnetic nanostructure. RésuméAnisotropie magnétique de l'atome isolé aux îlots monocouches de Co/Pt(111). En étudiant les propriétés magnétiques de particules de Co auto assemblées sur une surface d'orientation (111) d'un monocristal de Pt, nous montrons comment l'anisotropie magnétique évolue de l'atome isolé aux îlots monocouches et aux films ultraminces. Nous trouvons que les atomes de Co isolés adsorbés en surface ont une énergie d'anisotropie magnétocrystalline de E a = 9.3 ± 1.6 meV/atome provenant de la combinaison d'un moment orbital conservé (m L = 1.1 µ B ) et d'un fort couplage spin-orbite induit par le substrat de Pt. Des expériences combinées de microscopie à effet tunnel et de dichroïsme circulaire magnétique à rayons X, effectués sur des îlots de Co de petit taille établissent une connexion claire entre E a et m L , chacune de ces quantités décroissant rapidement avec la coordination latérale des atomes magnétiques. En conformité avec ceci, nous trouvons en employant la magnétométrie par effet Kerr et le microscope à effet tunnel que l'énergie d'anisotropie de grands îlots bidimensionnels de Co est presque entiè-rement déterminée par le nombre relativement faible d'atomes au périmètre, ayant E a = 0.9 ± 0.1 meV/atome. Ces résultats confirment les prédictions théoriques et sont d'un intérêt fondamental pour comprendre comment l'anisotropie magnétique se développe dans les particules magnétiques de taille finie. L'identification du rôle des atomes au périmètre et des atomes de surface ouvre de nouvelles opportunités pour l'ingénierie de l'anisotropie et du moment de nanostructures magnétiques. Pour citer cet article : P. Gambardella et al., C. R. Physique 6 (200...

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Magnetic properties of finite Co chains on Pt(111)

Cited by 101 publications

References 28 publications

Ab initio study of canted magnetism of finite atomic chains at surfaces

Ab initio study of canted magnetism of finite atomic chains at surfaces

Finite-sized Heisenberg chains and magnetism of one-dimensional metal systems

Magnetic anisotropy from single atoms to large monodomain islands of Co/Pt(111)

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