Epitaxial growth of thin magnetic cobalt films on Au(111) studied by scanning tunneling microscopy

Voigtländer, Bert; Meyer, Gerhard; Amer, Nabil M.

doi:10.1103/physrevb.44.10354

Cited by 406 publications

(270 citation statements)

References 18 publications

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“…If L is the linear dimension of a particle and t its thickness, denoting by a 0 the in-plane atomic distance, one has N = γ(L/a 0 ) 2 (t/c 0 ), where γ is a geometric factor, depending on the shape of the particle and the lattice structure. The correction terms included in E (2) dip decay with distance as 1/D 5 , whilst the usual dipolar interaction decays as 1/D 3 . More precisely, E (2) dip is a factor I 12 /D 2 smaller than E (0) dip , where I 12 = 1 2 (I 1 + I 2 ) is the semisum of the "moments of inertia" I i of the two particles (see Appendix A).…”

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

“…The correction terms included in E (2) dip decay with distance as 1/D 5 , whilst the usual dipolar interaction decays as 1/D 3 . More precisely, E (2) dip is a factor I 12 /D 2 smaller than E (0) dip , where I 12 = 1 2 (I 1 + I 2 ) is the semisum of the "moments of inertia" I i of the two particles (see Appendix A).…”

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

“…Both E (0) 12 and E (2) 12 are the sum of competitive interactions. For the sake of definiteness, let us consider E (2) 12 .…”

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

“…For the sake of definiteness, let us consider E (2) 12 . The sum 2S z 1 S z 2 + S 1 · S 2 favours an antiferromagnetic (AFM) alignment of the spins in theẑ direction, perpendicular to their joining vector.…”

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

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Dipolar interaction between two-dimensional magnetic particles

2002

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We determine the effective dipolar interaction between single domain two-dimensional ferromagnetic particles (islands or dots), taking into account their finite size. The first correction term decays as 1/D 5 , where D is the distance between particles. If the particles are arranged in a regular two-dimensional array and are magnetized in plane, we show that the correction term reinforces the antiferromagnetic character of the ground state in a square lattice, and the ferromagnetic one in a triangular lattice. We also determine the dipolar spin-wave spectrum and evaluate how the Curie temperature of an ensemble of magnetic particles scales with the parameters defining the particle array: height and size of each particle, and interparticle distance. Our results show that dipolar coupling between particles might induce ferromagnetic long range order at experimentally relevant temperatures. However, depending on the size of the particles, such a collective phenomenon may be disguised by superparamagnetism.

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Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

“…Both E (0) 12 and E (2) 12 are the sum of competitive interactions. For the sake of definiteness, let us consider E (2) 12 .…”

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

Section: Effective Dipolar Interaction Between Particlesmentioning

confidence: 99%

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Dipolar interaction between two-dimensional magnetic particles

2002

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“…Due to preferred nucleation of metal islands at the elbow sites of a reconstructed surface, [22] Fe or Co nanoarrays are readily obtained. [23,24] Islands of monoatomic height evolve as a consequence of Fe deposition, whereas bilayer dots are encountered with Co deposition. In agreement with earlier findings, the STM data confirm that the Au (111) reconstruction is maintained as demonstrated in the exemplary results in Figure 1.…”

mentioning

confidence: 99%

Mesoscopic Metallosupramolecular Texturing by Hierarchic Assembly

et al. 2005

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Currently, there is a strong interest in improving the fabrication and mesoscopic integration of functional nanosystems at surfaces. In particular, new pathways need to be developed to provide methodologies for the synthesis and embedding of nanostructures across multiple length scales. [1][2][3][4] Herein, we introduce the combination of nanopatterning and controlled metal-organic assembly to process prestructured metallic templates and generate arrangements at a higher hierarchical level. We present results of scanning tunneling microscopy (STM) on the metal-directed assembly and mesoscopic organization of supramolecular architectures by using a textured metal substrate, that is, an Au(111) surface decorated with Fe or Co nanodot arrays. By tuning the local reaction conditions with co-deposited dicarboxylate linker molecules, distinct low-dimensional metallosupramolecular systems have been synthesized, which include regularly spaced iron terephthalate ribbons that form a grating whose extension is only limited by the substrate terrace morphology. These findings indicate that hierarchic assembly protocols blending physical nanopatterning [5][6][7][8][9] and supramolecular engineering [10][11][12][13] on surfaces are generally useful for fabricating nanomaterials with control of features at the mesoscopic level.Metal-directed self-assembly of functional molecules provides a versatile strategy towards highly organized supramolecular systems. [14][15][16][17] Recent findings reveal that similar processes can be conducted at surfaces, where notably a series of metal-carboxylate architectures were generated, including mononuclear arrays, ladder structures, and nanoporous 2D metal-organic coordination networks. [13,[18][19][20][21] However, until now these systems have been constructed on homogeneous substrates on which typically organic layers were exposed to a flux of metal atoms. To control the spatial distribution of surface coordination architectures, it is promising to explore prestructured surfaces, which-due to their intrinsic anisotropy, local concentration of reactants and site reactivityallow us to direct and confine the assembly. This control is not possible with homogeneous substrates. Herein we present a temperature-controlled STM investigation of the steering of metallosupramolecular reticulation by using nanopatterned templates. This approach is a model for a two-stage assembly that combines self-organized metal-on-metal growth followed by chemical processing. This methodology may allow the fabrication of low-dimensional functional nanosystems, steer the formation of (metallo-) supramolecular assemblies, enable the study and control of metal-molecule interfacing, or structure template layers in the 100 nm regime for handling nanoscale objects.Specifically, we employed regular lattices of transition metal dots by depositing small amounts of cobalt or iron on Au(111) at room temperature. Due to preferred nucleation of metal islands at the elbow sites of a reconstructed surface, [22] Fe or Co nanoarrays ...

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Magnetic Domains and Anisotropy in Ultrathin Au/Co/Au Wedges Deposited on Mica Substrates

Kisielewski

Kurant

Maziewski

et al. 2002

phys. stat. sol. (a)

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Ultrathin cobalt films and wedges in gold envelope Au/Co(d Co < 2.5 nm)/Au(111), were deposited by molecular beam epitaxy (MBE) on mica. The topography of the Co layer (before covering with Au) and the influence of annealing were studied in-situ by scanning tunneling microscopy. Selforganization of the cobalt deposit in nanometer sized chains was observed. Magnetization processes and domain structure were studied ex-situ using the polar Kerr effect in both magnetooptical magnetometer and magnetooptical microscope. Two anisotropy constants K 1 and K 2 (> 0) were determined for samples with different thicknesses. Annealing induced in the sample: (i) flattening of the cobalt surface; (ii) a decrease of the coercivity field and magnetic anisotropy caused a decrease of thickness of reorientation from easy axis state to easy plane one; (iii) an increase of the Barkhausen volume which contains many cobalt "islands" creating the chains. Approaching the reorientation region, the character of the magnetization reversal drastically changes from that with the preference of domain wall propagation into the one connected to the domain wall nucleation.A series of in-situ works have been performed on ultrathin cobalt deposited on Au(111) single crystal. First, magnetic domain structures were observed by SEMPA ten years ago [1]. Drastic changes of the domain structure with film thickness were observed for cobalt wedges [2,3]. A huge influence of heat treatment on the magnetic microstructure [2,4] was correlated with the modifications of the film morphology. Domains in Co/Au(111) single crystals were also investigated as a function of the film thickness and carbon content applying magnetic force microscopy under ultrahigh vacuum conditions [5]. However, the complex studies on the domain structure and magnetic anisotropy, requiring a proper amplitude and orientation of the magnetic field at the sample, are quite complicated for the in-situ performance. For ex-situ magnetooptics and domain structure studies, inexpensive substrates, especially annealed (111)-textured Au films on glass were used. However, they were not fully comparable with Au single crystalline substrates [6][7][8]. The aim of the present paper is to study ex-situ domain and magnetic anisotropy of well in-situ characterized ultrathin cobalt films deposited on high quality Au(111) substrates obtained on mica.

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Epitaxial growth of thin magnetic cobalt films on Au(111) studied by scanning tunneling microscopy

Cited by 406 publications

References 18 publications

Dipolar interaction between two-dimensional magnetic particles

Dipolar interaction between two-dimensional magnetic particles

Mesoscopic Metallosupramolecular Texturing by Hierarchic Assembly

Magnetic Domains and Anisotropy in Ultrathin Au/Co/Au Wedges Deposited on Mica Substrates

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