Preparation of well-ordered cobalt nanostructures on Au(111)

Tölkes, Christian; Zeppenfeld, P.; Krzyzowski, Michael A.; David, Rudolf; Comşa, George

doi:10.1103/physrevb.55.13932

Cited by 40 publications

(17 citation statements)

References 21 publications

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“…7 We note that, while Au and Co are immiscible in the bulk, a partial exchange of Au and Co atoms may occur at an interface. 16,17 The substantial difference in values of 2 found for Au/Co and Au/Fe is probably due to the different initial growth modes of Co and Fe on the reconstructed Au surface: Co islands show a bilayer growth, 18 in contrast to the monolayer growth of Fe. 19 The formation of an interface-confined mixture at the Au/Co interface will effectively decrease t Au .…”

Section: Structural Characterizationmentioning

confidence: 97%

Interplay between superconductivity and ferromagnetism in epitaxial Nb(110)/Au(111)/Co(0001) trilayers

2010

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Epitaxially grown multilayer systems offer the possibility to study the influence of ferromagnetism on superconductivity in a controlled way. In this paper, we explore how the superconducting properties of high quality epitaxially grown superconductor/normal-metal/ferromagnet trilayers evolve as a function of the exchange splitting in the ferromagnet and the thickness of the normal-metal layer. We report results for Nb͑110͒/ Au͑111͒/Co͑0001͒ and make a detailed comparison with earlier results for Nb͑110͒/Au͑111͒/Fe͑110͒. We use quantitative fast Fourier transform analysis to confirm the existence of a long-period ͑2.1 nm͒ oscillation in the superconducting transition temperature T c as a function of the Au-layer thickness t Au for t Au Ͼ 2 nm and highlight an additional short-period ͑0.76 nm͒ oscillation for t Au Ͻ 3 nm in Nb/Au/Co. This short-period oscillation can be explained in terms of a damped Ruderman-Kittel-Kasuya-Yoshida-like oscillation of the spin polarization in Au. The robustness of the long-period oscillation against the substitution of Co for Fe suggests that it is intrinsic to the Au͑111͒ layer on Nb and may represent a form of quantum interference in very clean trilayer systems.

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Section: Structural Characterizationmentioning

confidence: 97%

Interplay between superconductivity and ferromagnetism in epitaxial Nb(110)/Au(111)/Co(0001) trilayers

2010

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“…23 In the submonolayer regime, Co forms dots with an apparent height of 4.1Å, corresponding to the distance between two hcp Co(0001) planes. 11,24 The dots are well arranged in arrays driven by the Au reconstruction. Inside a unit cell (7 × 25 nm 2 with the long lattice parameter slightly varying along the sample), two nanoislands are arranged.…”

Section: A Growth Of Co/pt Supported Nanodotsmentioning

confidence: 99%

Interplay between interfacial and structural properties on the magnetism of self-organized core-shell Co/Pt supported nanodots

et al. 2011

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We have studied the influence of Pt capping on the magnetic properties of self-organized Co nanodots by means of complementary structural and magnetic investigation techniques. The growth of monodisperse 5 nm diameter Co dots on a Au(111) surface and its progressive coverage by Pt were performed under ultrahigh vacuum conditions and imaged by scanning tunneling microscopy, revealing a weak mixing at room temperature. The Co/Pt core-shell structure was studied both by molecular-dynamics simulations and surface extended xray-absorption fine structure, showing a global dilatation of the Co core. Both magnetic moments and hysteresis cycles at various temperatures were measured using x-ray magnetic circular dichroism, revealing a slight increase of the magnetic moments and the out-of-plane magnetic anisotropy after Pt capping. Moreover, the variation of magnetic anisotropy as a function of capping was followed in situ by the magneto-optical Kerr effect. Our investigations demonstrate that interfacial hybridization between Co and Pt is dominant over magnetoelastic contribution in this system.

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“…These include sandwichlike growth where atoms from a low surface-energy substrate climb on top of the overlayer. [2][3][4] Other possibilities of more relevance in this study include the development of bilayer islands on single-element metal substrates [4][5][6][7][8] and on alloy substrates. [9][10][11] The development of flat-topped or mesalike multilayer islands has also been observed on single-element metal substrates [12][13][14][15][16] and on alloys.…”

Section: Introductionmentioning

confidence: 99%

Formation and coarsening of Ag(110) bilayer islands on NiAl(110): STM analysis and atomistic lattice-gas modeling

et al. 2010

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Scanning tunneling microscopy analysis of the initial stages of film growth during deposition of Ag on NiAl(110) reveals facile formation of bilayer Ag(110) islands at temperatures of 130 K and above. Annealing subsequent to deposition at 130 K induces coarsening of the bilayer island distribution. The thermodynamic driving force for bilayer island formation reflects a lower relative surface energy for films of even layer thicknesses. This feature derives from quantum size effects due to electron confinement in the Ag film. The kinetics of island formation and relaxation is controlled by terrace and edge-diffusion barriers, detachment barriers, interlayer diffusion barriers, and layer-dependent adsorption and interaction energies. These key energies are determined from density-functional theory analysis and incorporated into an atomistic lattice-gas model for homogeneous island formation, where specification of the adatom hop rates is consistent with detailed balance. Model analysis via kinetic Monte Carlo simulation elucidates the role of strongly anisotropic interactions in development during deposition of elongated island growth shapes and also in facilitating upward mass transport needed for bilayer island formation. The model succeeds in recovering island densities at lower temperatures but experimental densities exceed model predictions at higher temperatures plausibly due to heterogeneous nucleation at surface defects. The same model successfully describes postdeposition coarsening of small islands grown at 130 K. Scanning tunneling microscopy analysis of the initial stages of film growth during deposition of Ag on NiAl͑110͒ reveals facile formation of bilayer Ag͑110͒ islands at temperatures of 130 K and above. Annealing subsequent to deposition at 130 K induces coarsening of the bilayer island distribution. The thermodynamic driving force for bilayer island formation reflects a lower relative surface energy for films of even layer thicknesses. This feature derives from quantum size effects due to electron confinement in the Ag film. The kinetics of island formation and relaxation is controlled by terrace and edge-diffusion barriers, detachment barriers, interlayer diffusion barriers, and layer-dependent adsorption and interaction energies. These key energies are determined from density-functional theory analysis and incorporated into an atomistic lattice-gas model for homogeneous island formation, where specification of the adatom hop rates is consistent with detailed balance. Model analysis via kinetic Monte Carlo simulation elucidates the role of strongly anisotropic interactions in development during deposition of elongated island growth shapes and also in facilitating upward mass transport needed for bilayer island formation. The model succeeds in recovering island densities at lower temperatures but experimental densities exceed model predictions at higher temperatures plausibly due to heterogeneous nucleation at surface defects. The same model successfully describes postdeposition coarsenin...

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Preparation of well-ordered cobalt nanostructures on Au(111)

Cited by 40 publications

References 21 publications

Interplay between superconductivity and ferromagnetism in epitaxial Nb(110)/Au(111)/Co(0001) trilayers

Interplay between superconductivity and ferromagnetism in epitaxial Nb(110)/Au(111)/Co(0001) trilayers

Interplay between interfacial and structural properties on the magnetism of self-organized core-shell Co/Pt supported nanodots

Formation and coarsening of Ag(110) bilayer islands on NiAl(110): STM analysis and atomistic lattice-gas modeling

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