The structure of ultrathin iron films on tungsten single-crystal surfaces

Gardiner, T.M.

doi:10.1016/0040-6090(83)90287-0

Cited by 36 publications

(19 citation statements)

References 8 publications

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“…The corresponding heat of formation that we calculated for FM 1 ML Fe/W(100) is −0.62 eV/atom, which is nearly the same as the value, −0.57 eV/atom, that was determined earlier [48]. Fe films up to 2 ML thick have been shown experimentally to be thermodynamically stable [33,35,40,[44][45][46]. This empirical observation suggests a small margin of error in the theoretical treatment and that 2 ML films must really be marginally stable.…”

Section: B Magnetic Ground State Magnetic Moments and Heats Of Forsupporting

confidence: 71%

“…The 2 ML wetting layer has been shown experimentally to be thermodynamically stable [33,35,40,[44][45][46]. Material in excess of the thermodynamically stable wetting layer thickness agglomerates into three-dimensional (3D) islands upon annealing or directly during growth at elevated temperature [33][34][35]38,40,41,[44][45][46]. Films grown at room temperature exhibit in-plane magnetization [37,38,[40][41][42]45].…”

Section: B Film Growth and Magnetic Onsetmentioning

confidence: 99%

“…It is well known that highly strained (10.4%) pseudomorphic films form at room temperature [34,35,40,41,[43][44][45] that become increasingly rough with increasing thickness above an initial wetting layer thickness of 2 ML [41, 44,45]. The 2 ML wetting layer has been shown experimentally to be thermodynamically stable [33,35,40,[44][45][46]. Material in excess of the thermodynamically stable wetting layer thickness agglomerates into three-dimensional (3D) islands upon annealing or directly during growth at elevated temperature [33][34][35]38,40,41,[44][45][46].…”

Section: B Film Growth and Magnetic Onsetmentioning

confidence: 99%

“…The growth and wetting behavior of Fe films on the W(100) surface have been studied previously [33][34][35][36][37][38][40][41][42][43][44][45][46][47]. It is well known that highly strained (10.4%) pseudomorphic films form at room temperature [34,35,40,41,[43][44][45] that become increasingly rough with increasing thickness above an initial wetting layer thickness of 2 ML [41, 44,45].…”

Section: B Film Growth and Magnetic Onsetmentioning

confidence: 99%

“…The growth and magnetic properties of Fe films on the W(100) surface have been studied theoretically and experimentally in the past [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. In this paper, we make a comparative experimental and theoretical study of Fe films on the W(100) surface and W(100)-M c(2 × 2) (M = Cu, Ag, Au) surface alloy substrates.…”

Section: Introductionmentioning

confidence: 99%

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Controlling magnetic interfaces using ordered surface alloys

Ji¹

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We have investigated the growth and magnetic properties of Fe thin films on the clean W(100) surface and W(100)-M c(2 × 2) (M = Cu, Ag, Au) surface alloy substrates. The influence of the interface on magnetism is assessed experimentally by studying sensitive threshold behavior in magnetic ordering using spin-polarized low-energy electron microscopy. The onset of ferromagnetic order that occurs with increasing film thickness at room temperature due to finite-sized scaling of the Curie temperature varies reproducibly among films on W(100) and the surface alloys. Magnetic moments and exchange coupling constants of the magnetic ground states are also determined theoretically for films with ideal interfaces by first-principles density functional theory calculations. These microscopic quantities are consistently enhanced in Fe films on the noble metal-induced surface alloys compared to their values in films on the clean W(100) surface. We attribute the systematic variation of magnetic onset observed experimentally to the competition between the intrinsically enhanced magnetic coupling and moments on the surface alloy substrates and several extrinsic factors that could suppress magnetic ordering, including intermixing, substrate and film roughness, and surface alloy disorder. Tendencies for intermixing are explored theoretically by determining the energy barrier for noble metal segregation. Despite these possible extrinsic effects, the results suggest that the use of the broad class of ordered surface alloys as alternative substrates may offer greater opportunities for manipulating thin film magnetism.

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Section: B Magnetic Ground State Magnetic Moments and Heats Of Forsupporting

confidence: 71%

Section: B Film Growth and Magnetic Onsetmentioning

confidence: 99%

Section: B Film Growth and Magnetic Onsetmentioning

confidence: 99%

Section: B Film Growth and Magnetic Onsetmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Controlling magnetic interfaces using ordered surface alloys

Ji¹

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4.2 Electron work function of metals and semiconductors

Jakobi¹

2002

Landolt-Börnstein - Group III Condensed Matter

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If an electron beam is directed towards a surface, it gets reflected if its potential is equal to -(E P /e + ∆Φ), the negative value of the primary energy divided by e and corrected for ∆Φ between the surface and the electron emitter (in the widest sense: cathode, electron gun, etc.). Since the surface serves here as the anode in a diode configuration, the name diode method has been chosen. This method was introduced early by P.A. Anderson [35A]. Many details of different experimental set-ups are discussed in [73K2, 79H3]. It was pointed out [85K8] that for carefully chosen conditions and for a patchy surface, i.e., a surface consisting of a composite of smaller areas of different work function, the diode method measures the same arithmetical average of Φ as the Kelvin method (see below). How to use a HREEL spectrometer for the diode method is reported in Ref.[85S3]. Vibrating capacitor method (Kelvin)The vibrating capacitor method is based on the work of Lord Kelvin [1898K] and of Zisman [32Z]. A condensor is formed of the surface to be studied and a reference electrode in front of it which are connected by a ammeter and a variable voltage source. If the capacitance between the plates (sample and reference electrode) is changed, e.g., by changing their distance, a current will flow. By compensating the Ref. p. 4.2-118] 4.2 Electron work function of metals and semiconductors Lando lt-Börnstein New Series III/42A2 4.2-7contact potential difference through the voltage source, the current can be brought to zero. Since Φ of the surface is part of the contact potential, its changes relative to the reference electrode can be measured. A more extended description can be found in Ref. [79H3]. A very versatile instrument of this kind was developed by Besocke [76B]. Data collectionData have been collected for metal as well as semiconductor substrates. In the case of metals only elemental, single-crystalline samples were considered. There are a few exceptions to this general rule. Some metallic alloys are listed in case of single-crystalline samples of well defined (stoichiometric) composition. Some data are also incorporated for evaporated, mostly polycrystalline films of materials for which no single-crystal data are available. For semiconductor substrates, adsorbate-induced workfunction changes consist of two contributions: band-bending and electron-affinity changes. Systems were discarded for which the overall change in work function was small (<0.2 eV) or for which the authors did not report a separation of the two contributions. With respect to the adsorbates, only single-component adsorption layers were considered, i.e., co-adsorbates were omitted. Furthermore, it should be noted that completeness -although intended -could not be achieved. It was learned that work-function data are very often not in the center of a publication. Work-function data even seemed to many authors too marginal to give explicitly reference to them in the title, abstract or key words. Therefore, also computer based research could not guarant...

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Figures for 4.2

Jakobi¹

2002

Landolt-Börnstein - Group III Condensed Matter

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The structure of ultrathin iron films on tungsten single-crystal surfaces

Cited by 36 publications

References 8 publications

Controlling magnetic interfaces using ordered surface alloys

Controlling magnetic interfaces using ordered surface alloys

4.2 Electron work function of metals and semiconductors

Figures for 4.2

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