Origin of the magnetic anisotropy in ferromagnetic layers deposited at oblique incidence

Bubendorff, Jean-Luc; Zabrocki, Stephan; Garreau, G.; Hajjar, S.; Jaafar, Rached; Berling, Dominique; Mehdaoui, A.; Pirri, C.; Gewinner, G.

doi:10.1209/epl/i2006-10089-5

Cited by 55 publications

(54 citation statements)

References 19 publications

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“…[ 20,21 ] OID is also well applicable for adjustment of the magnetic anisotropy in fi lms with a thickness of a few nm. [ 19 ] Here, we show that OID can be applied in an elegant way to arbitrarily stack custom-made magnetic layers to form new magnetic materials by design. This constitutes a qualitatively new feature with a huge impact for engineering of spintronic systems and magnetic multilayers in general.…”

Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 91%

“…[17][18][19] OID is highly suitable for fabrication of customized arrays of 3D nano-objects with high aspect ratio. Based on particle beam shadowing, nanorods, nanospirals or zig-zag structures can be prepared by a proper sequence of deposition steps.…”

Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 99%

“…The microscopic origin of this effect is a wavy surface topography with a highly anisotropic correlation function. [ 19 ] Dipolar stray fi elds originating from this rough surface cause a preferred orientation of the magnetic moments and defi ne a uniaxial magnetic anisotropy. The amplitude of the surface profi le increases with growing fi lm thickness as well as with increasing polar angle θ , and likewise does the strength of this magnetic shape anisotropy.…”

Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 99%

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Spin‐Structured Multilayers: A New Class of Materials for Precision Spintronics

Schlage

Bocklage

Erb

et al. 2016

Adv Funct Materials

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7423wileyonlinelibrary.com extensively explored to maximize the magnitude of the magnetoresistive signal, which is defi ned as the normalized difference of the electrical resistance in the antiparallel and parallel magnetic confi guration of the trilayer. The basic GMR and TMR characteristics of spintronic devices and thus their functionalities, however, did not signifi cantly change during the last decade. This is due to conventional magnetic multilayer design and its limitations based on the interplay of accessible magnetic anisotropy contributions. Here, we show that oblique incidence deposition (OID) can be used in an elegant way to achieve full control on the magnetic anisotropy in every individual layer of such magnetoresistive multilayer stacks for the fi rst time. The additional shape anisotropy component introduced via OID allows for arbitrarily crossed magnetic easy axes with adjustable switching fi elds and opens a path for customized spintronic devices with conceptually new functionalities.So far, two major approaches have been pursued to engineer fi eld-dependent relative magnetic confi gurations of two ferromagnetic layers. In the fi rst case, one of the ferromagnetic layers either exhibits an enhanced coercive fi eld or is magnetically pinned (exchange biased) by an additional antiferromagnetic layer of high magnetic anisotropy. Thus, only the magnetically uncoupled free layer follows small external fi elds, causing a change of the magnetic confi guration and the magnetoresistance. [ 13 ] In the second approach, an interlayer exchange coupling, the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction, is used to align both layers relative to each other. [ 14 ] The interlayer coupling defi nes the magnetic saturation behavior and hence the functionality of the trilayer. In conventional systems, only parallel or antiparallel orientations of the ferromagnetic layers are reliably achieved. Effi cient RKKY coupling is observed for particular material combinations only and depends very sensitively on the interlayer thickness. [ 15,16 ] Therefore, conventional magnetic multilayer design is restricted to a limited number of magnetic confi gurations in the trilayers which constrains the design and control of magnetic spin structures that are available for realizing particular magnetoelectronic responses.Our approach enables one to realize and tune magnetic and magnetoresistive properties in spintronic multilayer systems that exceed the potential of conventional approaches by far. The technique is not based on exchange-bias or interlayer coupling and is not affected by their limitations. Every ferromagnetic layer of arbitrary chemical composition, as a constituent either Spin-Structured Multilayers: A New Class of Materials for Precision SpintronicsKai Schlage , * Lars Bocklage , Denise Erb , Jade Comfort , Hans-Christian Wille , and Ralf Röhlsberger * Magnetoelectronic multilayer devices are widely used in today's information and sensor technology. Their functionality, however, is limited by the inherent prop...

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Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 91%

Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 99%

Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 99%

See 1 more Smart Citation

Spin‐Structured Multilayers: A New Class of Materials for Precision Spintronics

Schlage

Bocklage

Erb

et al. 2016

Adv Funct Materials

View full text Add to dashboard Cite

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“…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].…”

mentioning

confidence: 99%

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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“…However, while there are numerous experimental investigations of obliquely deposited thin magnetic films (see, for example, Ref. [2]), to our knowledge, only a few theoretical works are present [6,7]. In this work, we use Monte Carlo film growth simulator to generate three-dimensional thin-film structures with columnar morphology for simulation of their magnetic properties by means of micromagnetic modeling.…”

Section: Introductionmentioning

confidence: 99%