Growth, thermal stability and magnetism of Ni ultrathin films on O-3×3/W(111) surface

Tsai, Cheng Jui; Hsueh, Kun Jen; Plusnin, N.I.; Kuo, Chien Cheng; Lin, Wen Chin

doi:10.1016/j.apsusc.2014.05.180

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…Although the chemisorbed oxygen phase and its influence on the structural, − magnetic, ,− and electronic ,, surface properties have been deeply investigated for a large number of metals, much less is known about the oxide phase, especially concerning the early stages of oxide nucleation. In particular, the number of experimental investigations performed by means of scanning tunneling microscopy (STM) is scarce − if compared to other surface-sensitive spatial-averaging techniques.…”

Section: Introductionmentioning

confidence: 99%

Atomic Scale Insights into the Early Stages of Metal Oxidation: A Scanning Tunneling Microscopy and Spectroscopy Study of Cobalt Oxidation

et al. 2016

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Understanding the mechanisms driving the early stages of oxidation of metallic surfaces is of fundamental importance in fields such as nanocatalysis, electrochemistry, and nanoelectronics. In this work, the early stages of oxidation of ultrathin Co films deposited on the Fe(001)-p(1 × 1)O surface have been investigated by means of Auger electron spectroscopy, scanning tunneling microscopy, and scanning tunneling spectroscopy. The oxidation is initiated by homogeneous oxide nucleation over the atomically flat Co terraces, inducing the development of a smooth oxide wetting layer when the islands coalesce. Atomically resolved images reveal that the oxide wetting layer is highly defective, possibly due to the presence of oxygen vacancies. Constant current scanning tunneling microscopy images acquired in different tunneling conditions, as well as scanning tunneling spectroscopy, reveal the distinct electronic properties of the oxide nuclei with respect to the chemisorbed phase. The fundamental band gap develops since the early stages of oxide nucleation. Moreover, spectroscopic curves acquired in the near-field-emission regime reveal a significant lowering of the sample work function induced by the oxide development. Our results represent a remarkable case in which metal oxidation can be studied at the atomic-scale level.

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Section: Introductionmentioning

confidence: 99%

Atomic Scale Insights into the Early Stages of Metal Oxidation: A Scanning Tunneling Microscopy and Spectroscopy Study of Cobalt Oxidation

et al. 2016

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“…Theoretical and experimental efforts have highlighted a rich phenomenology of adsorbate-induced effects, such as modifications of the work function [1,2] or surface electronic structure [3,4], enhanced [5][6][7] or tailored [8][9][10][11][12][13][14] surface magnetism, and structural relaxations [15][16][17][18], just to name a few. Aside from the above-mentioned phenomena, a widely investigated topic is the so-called surfactant-assisted epitaxial growth [19][20][21][22][23][24]. In this case, a monolayer (or less) of foreign atoms adsorbed on the substrate before film deposition strongly influences the film morphology, both for heteroepitaxy and homoepitaxy.…”

Section: Introductionmentioning

confidence: 99%

Mesoscopic organization of cobalt thin films on clean and oxygen-saturated Fe(001) surfaces

et al. 2015

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The different morphologies of Co films grown on either the clean Fe(001) surface and the oxygen-saturated Fe(001)-p(1 × 1)O substrate are investigated by means of scanning tunneling microscopy, Auger electron spectroscopy, and density functional theory. The considered Co coverage range extends beyond the thickness at which layer-by-layer growth is destabilized by plastic deformations induced by the relaxation of the strain accumulated in the film. Our findings indicate that the oxygen overlayer of the Fe(001)-p(1 × 1)O surface floats on top of the growing Co film and strongly influences both the Co nucleation process and the film structural evolution. The layer-dependent islands nucleation of Co films grown on clean Fe(001) substrates, recently associated with a thickness-dependent adatom mobility [A. Picone et al., Phys. Rev. Lett. 113, 046102 (2014)], is found to be suppressed by the oxygen overlayer. The latter also significantly delays the layer-by-layer instability with respect to the oxygen-free growth. Furthermore, the body-centered-tetragonal/hexagonal-close-packed transition is not observed in the case of Co/Fe(001)-p(1 × 1)O sample, replaced by the development of highly ordered surface undulations. These form a mesoscopic square pattern with the sides aligned to the Fe 110 directions, while the surface atomic structure retains the square p(1 × 1) symmetry in registry with the substrate. Such undulations are likely generated by a highly ordered array of interfacial misfit dislocations running along the Fe 110 directions.

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“…The investigations of well-controlled transition metals on metallic substrates are an important topic in material science because of their scientific significance as well as technological applications, especially in surface alloying, microelectronics, enhancing catalytic activities, and spintronics. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] For instance, adsorption of oxygen on Ag/Pt(111) surface alloy leads to an attractive interaction between adsorbed oxygen atoms while oxygen adsorption is blocked on Ag sites. 1 By optimizing the Pt surface content or the Pt film thickness, unambiguous demonstrations of bimetallic surfaces reaching activities well in excess of that of Pt(111) have been made.…”

mentioning

confidence: 99%

Layered structure and related magnetic properties for annealed Fe/Ir(111) ultrathin films

Jiang

Chen

Hsieh

et al. 2015

Journal of Applied Physics

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After annealing treatments for fcc-Fe/Ir(111) below 600 K, the surface layers remain pseudomorphic. The Ir(111) substrate plays an important role on the expanded Fe lattice. At temperatures between 750 and 800 K, the surface composition shows a stable state and a c(2 × 4) structure is observed. We discover a layered structure composed of some Fe atoms on the top of a Fe0.5Ir0.5 interfacial alloy supported on the Ir(111) substrate. The competition between the negative formation heat of Fe0.5Ir0.5 and surface free energy of Fe causes the formation of layered structure. The existence of ferromagnetic dead layer coincides with the formation of fcc-Fe for ultrathin Fe on Fe0.5Ir0.5/Ir(111). For Fe films thicker than three monolayers, the linear increase of the Kerr intensity versus the Fe coverage is related to the growing of bcc-Fe on the surface where the Fe layer is incoherent to the underlying Fe0.5Ir0.5/Ir(111). These results emphasize the importance of the substrate induced strain and layered structure of Fe/Fe0.5Ir0.5/Ir(111) on the magnetic properties and provide valuable information for future applications.

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Growth, thermal stability and magnetism of Ni ultrathin films on O-3×3/W(111) surface

Cited by 4 publications

References 28 publications

Atomic Scale Insights into the Early Stages of Metal Oxidation: A Scanning Tunneling Microscopy and Spectroscopy Study of Cobalt Oxidation

Atomic Scale Insights into the Early Stages of Metal Oxidation: A Scanning Tunneling Microscopy and Spectroscopy Study of Cobalt Oxidation

Mesoscopic organization of cobalt thin films on clean and oxygen-saturated Fe(001) surfaces

Layered structure and related magnetic properties for annealed Fe/Ir(111) ultrathin films

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