Imaging the Magnetic Spin Structure of Exchange-Coupled Thin Films

Röhlsberger, Ralf; Thomas, H.; Schlage, Kai; Burkel, E.; Leupold, O.; Rüffer, R.

doi:10.1103/physrevlett.89.237201

Cited by 115 publications

(83 citation statements)

References 25 publications

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“…This method relies on the 14.4 keV nuclear magnetic dipole transition of the Mössbauer isotope 57 Fe which constitutes a very sensitive probe of the magnetization directions in a sample. [ 25,28 ] While the conventional electronic refl ectivity curve depends on the electron density depth profi le of the multilayer, the nuclear resonant refl ectivity curve is sensitive to the depth profi le of magnetization orientations in the sample. In particular, if the period of the magnetic structure does not coincide with the period of the chemical structure of the multilayer, magnetic superstructure peaks in the resonantly scattered intensity appear at corresponding angular positions.…”

Section: Methodsmentioning

confidence: 99%

“…[24][25][26] The technique is highly suited to accurately A) The sequence of azimuthal deposition angles for subsequent Fe layers ( α = +40°, 0°, 0°, 0°) results in two magnetic sublattices enclosing an angle of Δ α = 40°. An external magnetic fi eld B ind = 100 mT is used to induce a canted antiparallel confi guration of the sublattices in which the vertical magnetic correlation length (Λ mag ) is four times the structural one Λ struc .…”

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

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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: Methodsmentioning

confidence: 99%

Section: Magnetic Anisotropy Control In Single Films Via Oblique Incimentioning

confidence: 99%

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

Schlage

Bocklage

Erb

et al. 2016

Adv Funct Materials

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“…37) Typically, the exchange interaction forces the direction of magnetic moments in the soft-magnetic layer at the interface to be the same as those in the hard-magnetic layer in this type of system. However, an external field applied orthogonal to the magnetization direction of the hard layer was thought to have the effect of changing the direction of magnetic moments in the soft layer to align with the applied field, as the effect reduced with increasing distance from the interface.…”

Section: Energy Domain Measurementmentioning

confidence: 99%

“…Noteworthy examples include the use of SR to study thin films, interfaces, and surfaces 37,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] in a superconductor 55) and in high-pressure experiments, [56][57][58][59] as well as spin ice 60) and diffusion. [61][62][63][64][65][66][67][68][69] The application of external perturbations that are synchronized to the pulse timing of SR is a unique method.…”

Section: Energy Domain Measurementmentioning

confidence: 99%

Condensed Matter Physics Using Nuclear Resonant Scattering

Seto

2013

J. Phys. Soc. Jpn.

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Mössbauer spectroscopy is a powerful and well-established method used in a wide variety of scientific applications. An outstanding feature of this method is that element specific information on electronic and phonon states can be obtained. The use of high-brilliance synchrotron radiation as an excitation source for Mössbauer measurements enables measurements to be recorded under extreme conditions such as high pressures, very high or very low temperatures, and strong external magnetic fields. In addition, the tunability of synchrotron radiation energy allows a wide range of nuclides to be used. Moreover, the use of synchrotron radiation enables the measurement of the element-and sitespecific phonon density of states. Another unique property of the method is the narrow energy width of the nuclear excited states, due to which the method is an effective tool for studying the slow dynamics of soft matter and glass transitions. The concepts and methods involved in these measurements are introduced and discussed, and the unique features of the methods are highlighted.

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“…The vertical sensitivity can be uniquely brought to the atomic level by selectively doping the system with isotopic probe layers at the depth of interest [25,26]. While the distribution of nuclear resonant scattering in reciprocal space allows us to identify lateral magnetic correlations in a lattice, its delayed temporal evolution after pulsed excitation contains site-selective information about magnetic moment orientations [25]; i.e., collecting the time dependent nuclear signal at different Bragg peak positions allows us to selectively probe magnetic substructures in the sample.Thus, nuclear time spectra are not only highly sensitive to the nanoscopic arrangement of magnetic moments but likewise sensitive to spin dynamics up to the GHz regime. Oscillation frequencies and precessional magnetic moment trajectories can be quantitatively analyzed [27,28].…”

mentioning

confidence: 99%

Nuclear Resonant Surface Diffraction of Synchrotron Radiation

et al. 2017

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Nuclear resonant x-ray diffraction in grazing incidence geometry is used to determine the lateral magnetic configuration in a one-dimensional lattice of ferromagnetic nanostripes. During magnetic reversal, strong nuclear superstructure diffraction peaks appear in addition to the electronic ones due to an antiferromagnetic order in the nanostripe lattice. We show that the analysis of the angular distribution together with the time dependence of the resonantly diffracted x rays reveals surface spin structures with very high sensitivity. This scattering technique provides unique access to laterally correlated spin configurations in magnetically ordered nanostructures and, in perspective, also to their dynamics. DOI: 10.1103/PhysRevLett.118.237204 Resonant magnetic x-ray scattering of synchrotron radiation [1][2][3] is an established tool to probe magnetism in crystalline systems, ultrathin films, and multilayer structures. It allows us to identify magnetic order as well as the magnitude and orientation of magnetic moments with high elemental specificity. Magnetic long range ordering leads to Bragg diffraction from which valuable structural magnetic information can be extracted. While the width of the Bragg peaks is coupled to the crystal quality or strain of magnetic lattices, their peak position and intensity yield lattice parameters, content of the unit cell, or the arrangement of magnetic moments. Monitoring these diffraction peaks under the influence of external fields, pressure, temperature variation, or growth thus enables a detailed in situ characterization of nanomagnetic systems.During the last few decades, resonant x-ray diffraction and reflectometry were extensively applied to reveal the magnetic structure of various crystalline alloys [4][5][6] and superlattices [7][8][9][10][11][12]. Despite the growing need for the characterization of extended patterned magnetic structures like spin ice [13,14] or Skyrmion thin film systems [15][16][17], only a few resonant magnetic x-ray diffraction studies on such systems were carried out [18][19][20][21]. Most of these studies were performed at the L 3 edges of Fe or Co and deal with the field dependent shape of nanostripe domain patterns [22,23]. Using resonant soft x-ray diffraction, Chesnel et al. studied the field dependent magnetic configuration in a dipolar coupled multilayer grating [24].Here we show that nuclear resonant surface diffraction provides unique insight into the magnetism of patterned nanostructures. Applicable to various alloys containing Mössbauer isotopes, the technique offers a significant number of features not accessible by other techniques. Nuclear diffraction discriminates the resonantly scattered (delayed) x rays from the dominating electronic (prompt) ones via time gating, enabling us to detect a pure magnetic signal with very high signal-to-noise ratio. This yields superior sensitivity to detect magnetic superstructures in low-dimensional systems, weak contributions of magnetic order in a lattice, or the smallest variations of magne...

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Imaging the Magnetic Spin Structure of Exchange-Coupled Thin Films

Cited by 115 publications

References 25 publications

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

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

Condensed Matter Physics Using Nuclear Resonant Scattering

Nuclear Resonant Surface Diffraction of Synchrotron Radiation

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