Tuning the domain wall orientation in thin magnetic strips using induced anisotropy

Cherifi, S.; Hertel, Riccardo; Locatelli, Andrea; Watanabe, Yoshio; Potdevin, G.; Ballestrazzi, Antonio; Balboni, M.; Heun, S.

doi:10.1063/1.2778466

Cited by 33 publications

(29 citation statements)

References 21 publications

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“…Provided they do not dominate the energy landscape [23], such "additional" in-plane anisotropies could be used to reinforce the effect of the shape anisotropy in a nanowire, which could stabilize magnetization as dimensions approach the superparamagnetic limit. In-plane anisotropy can also allow control over the velocity and Walker breakdown fields of domain walls [21].…”

Section: Introductionmentioning

confidence: 99%

Transverse and vortex domain wall structure in magnetic nanowires with uniaxial in-plane anisotropy

Bryan

Bance

Dean

et al. 2011

J. Phys.: Condens. Matter

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Micromagnetic and analytical models are used to investigate how in-plane uniaxial anisotropy affects transverse and vortex domain walls in nanowires where shape anisotropy dominates. The effect of the uniaxial anisotropy can be interpreted as a modification of the effective wire dimensions. When the anisotropy axis is aligned with the wire axis (θ a = 0), the wall width is narrower than when no anisotropy is present. Conversely, the wall width increases when the anisotropy axis is perpendicular to the wire axis (θ a =π/2). The anisotropy also affects the nanowire dimensions at which transverse walls become unstable. This phase boundary shifts to larger widths or thicknesses when θ a = 0, but smaller widths or thicknesses when θ a = π/2.2

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Section: Introductionmentioning

confidence: 99%

Transverse and vortex domain wall structure in magnetic nanowires with uniaxial in-plane anisotropy

Bryan

Bance

Dean

et al. 2011

J. Phys.: Condens. Matter

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“…To explain the shape and orientation of the domains, in some of these cases the anisotropy of the spin stiffness must be taken into account, 6,7 while in others only certain spatial orientations of the domain walls minimize the sum of the magnetostatic stray-field energy and the magnetocrystalline anisotropy energy. 8 In this Rapid Communication we report on a different mechanism on how the domain-wall orientation is linked to the crystal lattice. For an ultrathin Fe film, we found out that the Dzyaloshinskii-Moriya interaction ͑DMI͒ plays the crucial role accounting for the orientation of the walls and further for the type of the wall and the rotational direction of the magnetization in the wall.…”

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Dzyaloshinskii-Moriya interaction accounting for the orientation of magnetic domains in ultrathin films: Fe/W(110)

2008

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Combining relativistic first-principles calculations with a micromagnetic model, we establish the Dzyaloshinskii-Moriya interaction as an important mechanism in thin-film magnetism, determining the orientation of magnetic domains relative to the lattice, the type of domain wall, and the rotational direction of the magnetization in the wall. Applying the analysis to two monolayers Fe on W͑110͒, we provide an explanation for puzzling experimental data obtained by spin-polarized scanning tunneling microscopy. DOI: 10.1103/PhysRevB.78.140403 PACS number͑s͒: 75.70.Ak, 71.15.Mb, 75.60.Ch Understanding the nature of domains and domain walls in magnetic nanostructures has become an important issue in the field of spintronics as the controlled motion of domain walls opens up vistas for new types of memory and logic devices ͑e.g., Refs. 1 and 2͒. Domain walls in nanostructures and thin films are known to originate from the interplay of the quantum-mechanical exchange interaction ͑also expressed as spin stiffness͒, the magnetocrystalline anisotropy caused by the relativistic spin-orbit coupling ͑SOC͒, and the classical long-ranged magnetostatic contribution. Usually, the shape of the domains is at random or depends on the size and geometry of the sample. [3][4][5] In these instances there is no correlation between the relative orientation of the domains and the crystal lattice. For a few systems, however, the orientation and anisotropy of the crystal lattice matter. To explain the shape and orientation of the domains, in some of these cases the anisotropy of the spin stiffness must be taken into account, 6,7 while in others only certain spatial orientations of the domain walls minimize the sum of the magnetostatic stray-field energy and the magnetocrystalline anisotropy energy. 8 In this Rapid Communication we report on a different mechanism on how the domain-wall orientation is linked to the crystal lattice. For an ultrathin Fe film, we found out that the Dzyaloshinskii-Moriya interaction ͑DMI͒ plays the crucial role accounting for the orientation of the walls and further for the type of the wall and the rotational direction of the magnetization in the wall. The DMI is an antisymmetric exchange interaction that favors spatially rotating magnetic structures of a specific rotational direction.9,10 It vanishes in inversion-symmetric crystal structures; therefore, it can be excluded for most simple bulk materials. In surface or interface geometries, however, the inversion symmetry is broken and the DMI may become relevant.11 In a recent work 12 it was demonstrated for the first time that on some surfaces the DMI is so strong that it even dominates over the symmetric exchange interactions and induces a spatially rotating magnetic ground state.In this study, we describe the domain walls by a micromagnetic model in which the DMI is included. In contrast to earlier work, we determine all model parameters quantitatively from their electronic origin by first-principles calculations and thus we are able to draw conclusions on th...

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“…The appearance of the steps can be explained in terms of nucleation and propagation of domain walls (DWs) [8,9]. Consequently, understanding the influence of oblique incidence growth is very important because of its ability to control both magnetic anisotropy and surface morphology [10,11,12].Although shadowing effects have been studied in many magnetic systems, including Fe on MgO(001) [13] and Co on Cu(001) [14], the plane of oblique incidence was always kept parallel to the in-plane cubic easy axes of the magnetic layers. Here, we report on the influence of oblique deposition on the surface morphology and magnetic properties of Fe/MgO(001) films for deposition azimuth both along the Fe Fig.…”

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Surface morphology and magnetic anisotropy of Fe/MgO(001) films deposited at oblique incidence

Zhan

Haesendonck

Vandezande

et al. 2009

Applied Physics Letters

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We have studied surface morphology and magnetic properties of Fe/MgO(001) films deposited at an angle varying between 0 o and 60 o with respect to the surface normal and with azimuth along the Fe [010] or the Fe[110] direction. Due to shadowing, elongated grains appear on the film surface for deposition at sufficiently large angle. X-ray reflectivity reveals that, depending on the azimuthal direction, films become either rougher or smoother for oblique deposition. For deposition along Fe[010] the pronounced uniaxial magnetic anisotropy (UMA) results in the occurrence of "reversed" two-step and of three-step hysteresis loops. For deposition along Fe[110] the growth-induced UMA is much weaker, causing a small rotation of the easy axes.Magnetic anisotropy of epitaxial films and its relationship to surface morphology have attracted much attention in recent years [1]. Both film properties are intimately related to the molecular beam epitaxy (MBE) deposition process. Oblique incidence deposition results via a self-shadowing effect [2,3] in the formation of grains in the plane of the film that are elongated perpendicular to the incident flux direction and with aspect ratio increasing at larger deposition angle with respect to the surface normal [4]. Consequently, an in-plane uniaxial magnetic anisotropy (UMA) with easy axis perpendicular to the incident flux direction is induced during growth of the magnetic films [4,5,6]. UMA was found to play an important role in determining the magnetization reversal in thin films of cubic systems [7,8]. Depending on the strength and orientation of the UMA, hysteresis curves with one, two and three steps are observed in various films at different field orientation. The appearance of the steps can be explained in terms of nucleation and propagation of domain walls (DWs) [8,9]. Consequently, understanding the influence of oblique incidence growth is very important because of its ability to control both magnetic anisotropy and surface morphology [10,11,12].Although shadowing effects have been studied in many magnetic systems, including Fe on MgO(001) [13] and Co on Cu(001) [14], the plane of oblique incidence was always kept parallel to the in-plane cubic easy axes of the magnetic layers. Here, we report on the influence of oblique deposition on the surface morphology and magnetic properties of Fe/MgO(001) films for deposition azimuth both along the Fe Fig. 1(c)). The elongated grains are believed to result from a redistribution of the incident flux due long-range attractive forces [15,16]. During evaporation the incident Fe atoms arrive preferentially on top of already formed grains rather than behind these grains. This shadowing effect is also observed for film deposition at 60 o with azimuth along [110]. The Fe grains on the surface are rhombic in shape with typical length of 15 nm and typical width of 6 nm (see Fig. 1(d)). Based on the STM images we conclude that the self-shadowing effect can be neglected for a deposition angle below 30 o . Moreover, the self-shadowing effect is...

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Tuning the domain wall orientation in thin magnetic strips using induced anisotropy

Abstract: We report on a method to tune the orientation of in-plane magnetic domains and domain walls

Cited by 33 publications

References 21 publications

Transverse and vortex domain wall structure in magnetic nanowires with uniaxial in-plane anisotropy

Transverse and vortex domain wall structure in magnetic nanowires with uniaxial in-plane anisotropy

Dzyaloshinskii-Moriya interaction accounting for the orientation of magnetic domains in ultrathin films: Fe/W(110)

Surface morphology and magnetic anisotropy of Fe/MgO(001) films deposited at oblique incidence

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