Optimized epitaxial growth of Fe on Ag(001)

Bürgler, D. E.; Schmidt, C. M.; Schaller, D. M.; Meisinger, F.; Hofer, R.; Güntherodt, H.‐J.

doi:10.1103/physrevb.56.4149

Cited by 69 publications

(44 citation statements)

References 23 publications

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“…Fe was deposited by molecular beam epitaxy using a mixedtemperature growth process [20] to avoid Ag segregation at the surface of the Fe film. First, 5 ML of Fe were grown at 140 K as a Ag diffusion barrier, then 24 ML of Fe were deposited at RT in wedge geometry with a slope of ß4 ML/mm.…”

Section: Methodsmentioning

confidence: 99%

Voltage control of magnetic anisotropy in Fe films with quantum well states

2014

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The influence of a gate voltage on magnetic anisotropy is investigated in a thin Fe film epitaxially grown on a Ag(1,1,10) substrate and covered by MgO. Oscillations in step-induced magnetic anisotropy due to quantum well states (QWS) confined in the Fe film are observed and shown to persist up to room temperature at low Fe thicknesses. By systematically examining the voltage and thickness dependence of the magnetic hysteresis loop characteristics, we identify two distinct effects by which an applied voltage modifies the magnetic anisotropy. The first effect is due to voltage-induced changes to interfacial perpendicular magnetic anisotropy which, due to the vicinal geometry, leads to changes in the effective in-plane uniaxial magnetic anisotropy. A second effect is observed at lower film thicknesses and shows nonmonotonic voltage-induced effects on magnetic anisotropy. This nonmonotonic behavior coincides with the onset of significant QWS-induced effects on magnetic anisotropy and suggests a link between QWS-and voltage-induced anisotropy changes.

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Section: Methodsmentioning

confidence: 99%

Voltage control of magnetic anisotropy in Fe films with quantum well states

2014

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“…There is justification to assume that our thin Fe layers (13.5Å), deposited at 160°C, preferably grow with (200) texture on the (200)-textured Ag films throughout the entire multilayer. This type of orientation is favorable, since the two (200) surface lattices of bcc Fe and fcc Ag are in almost perfect in-plane registry after a mutual rotation of 45°about the surface normal [40], and Fe(200)/Ag(200) epitaxial growth [which often is labeled as Fe(001)/Ag(001) epitaxy] has been often reported in the literature [41][42][43]. Also, one has to consider in the XRD pattern that the atomic scattering factor (f 2 ) of Ag is significantly larger than that of Fe [44].…”

Section: Crystallographic Orientationmentioning

confidence: 99%

Influence of interfaces on the phonon density of states of nanoscale metallic multilayers: Phonon confinement and localization

Keune

Hong

et al. 2018

Phys. Rev. B

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Isotope-selective 57 Fe nuclear resonant inelastic x-ray scattering (NRIXS) measurements and atomic-layer resolved density functional theory (DFT) calculations were used to investigate the effect of interfaces on the vibrational (phonon) density of states (VDOS) of (001)-oriented nanoscale Fe/Ag and Fe/Cr multilayers. The multilayers in the experiment contained isotopically enriched 57 Fe monolayers as probe layers located either at the Fe/Ag or Fe/Cr interfaces or in the center of the Fe films. This allows probing of the vibrational dynamics of Fe sites either at the buried interfaces or in the center of the Fe films. For Fe/Ag multilayers, distinct differences were observed experimentally between the Fe-partial VDOS at the interface and in the center. At the Fe/Ag interface, the high-energy longitudinal-acoustic (LA) phonon peak of Fe near ∼35 meV is suppressed and slightly shifted to lower energy, and the low-energy part of the VDOS below ∼20 meV is drastically enhanced, as compared to the Fe-specific VDOS in the center Fe layers or in bulk Fe. Similar phenomena are found to a less degree in the Fe/Cr multilayers. The measured Fe-partial VDOS was used to determine the Fe site-selective vibrational thermodynamic properties of the multilayers. Our theoretical findings for the layer-dependent VDOS of the multilayers are in qualitative agreement with the experimental results obtained by NRIXS. For Fe/Ag multilayers, which are characterized by a large atomic mass ratio, the experimental and theoretical results demonstrate phonon confinement in the Fe layers and phonon localization at the Fe/Ag interfaces due to the energy mismatch between Ag and Fe LA phonons. These phenomena are reduced or suppressed in the Fe/Cr multilayers with their about equal atomic masses. Moreover, direction-projected Fe VDOS along the (nearly in-plane) incident x-ray beam was computed in order to address the intrinsic vibrational anisotropy of the Fe/Ag multilayer. We have also performed spin-resolved electronic band structure (DFT) calculations, predicting an enhanced magnetic moment (μ Fe = 2.8 μ B ) of the interfacial Fe atoms and a high electron spin polarization (79%) at the Fermi energy for the Fe/Ag interface, as compared to the case of Fe center layers. This is a result of charge transfer from Fe to Ag at the interface. On the contrary, Cr tends to donate electrons to Fe, thus reducing the interfacial Fe moment (μ Fe = 1.9 μ B ). This implies strong chemical bonding at the Fe/Ag and Fe/Cr interfaces, affecting the interfacial VDOS.

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“…The preparation is described in detail elsewhere. 19,20 All thicknesses have been precisely determined using a calibrated quartz-crystal monitor. The Fe thickness has been varied continuously between 0 and 8 nm for sample A and stepwise for sample B with discrete Fe thicknesses of 5,8,12,18,24,32,44, and 60 nm.…”

Section: A Sample Preparation and Experimental Moke Setupmentioning

confidence: 99%

Thickness dependence of linear and quadratic magneto-optical Kerr effects in ultrathin Fe(001) films

Büchmeier¹,

Schreiber

Bürgler

et al. 2009

Phys. Rev. B

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Magneto-optical ͑MO͒ Kerr effect ͑MOKE͒ magnetometry is one of the most widely employed techniques for the characterization of ferromagnetic thin-film samples. Some information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained without any knowledge of the optical and MO properties of the material. On the other hand, a quantitative analysis, which requires precise knowledge of the material's index of refraction n and the MO-coupling constants K and G, is often desirable, for instance, for the comparison of samples which are different with respect to ferromagnetic layer thicknesses, substrates, or capping layers. While the values of the parameters n and the linear MO-coupling parameter K reported by different authors usually vary considerably, the relevant quadratic MO-coupling parameters G even for Fe are completely unknown. Here, we report on measurements of the thickness dependence ͑0-60 nm͒ of the linear and quadratic magneto-optical effects in epitaxial bcc-Fe͑001͒ wedge-type samples performed at a commonly used laser wavelength of 670 nm. By fitting the thickness dependence we are able to extract a complete set of parameters n, K, ͑G 11 − G 12 ͒, and G 44 for the quantitative description of the MOKE response of bcc-Fe͑001͒. We find the parameters n, K, and G to significantly differ for films thinner than about 10 nm as compared to those for thicker films, which is indicative of a thickness dependence of the electronic properties or of surface contributions to the MOKE. The magnitude of the quadratic magneto-optical effect is found to be about one-third of the record values reported recently for Co 2 FeSi.

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Optimized epitaxial growth of Fe on Ag(001)

Cited by 69 publications

References 23 publications

Voltage control of magnetic anisotropy in Fe films with quantum well states

Voltage control of magnetic anisotropy in Fe films with quantum well states

Influence of interfaces on the phonon density of states of nanoscale metallic multilayers: Phonon confinement and localization

Thickness dependence of linear and quadratic magneto-optical Kerr effects in ultrathin Fe(001) films

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