Superconductivity assisted change of the perpendicular magnetic anisotropy in V/MgO/Fe junctions

AbstractControlling the perpendicular magnetic anisotropy (PMA) in thin films has received considerable attention in recent years due to its technological importance. PMA based devices usually involve heavy-metal (oxide)/ferromagnetic-metal bilayers, where, thanks to interfacial spin-orbit coupling (SOC), the in-plane (IP) stability of the magnetisation is broken. Here we show that in V/MgO/Fe(001) epitaxial junctions with competing in-plane and out-of-plane (OOP) magnetic anisotropies, the SOC mediated interaction between a ferromagnet (FM) and a superconductor (SC) enhances the effective PMA below the superconducting transition. This produces a partial magnetisation reorientation without any applied field for all but the largest junctions, where the IP anisotropy is more robust; for the smallest junctions there is a reduction of the field required to induce a complete OOP transition ($$H_\text {OOP}$$ H OOP ) due to the stronger competition between the IP and OOP anisotropies. Our results suggest that the degree of effective PMA could be controlled by the junction lateral size in the presence of superconductivity and an applied electric field. We also discuss how the $$H_\text {OOP}$$ H OOP field could be affected by the interaction between magnetic stray fields and superconducting vortices. Our experimental findings, supported by numerical modelling of the ferromagnet-superconductor interaction, open pathways to active control of magnetic anisotropy in the emerging dissipation-free superconducting spin electronics.

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Origin of perpendicular magnetic anisotropy in amorphous thin films

Scientific Reports ◽

10.1038/s41598-020-78950-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Daniel Lordan ◽

Guannan Wei ◽

Paul McCloskey ◽

Cian O’Mathuna ◽

Ansar Masood

Keyword(s):

Thin Films ◽

Magnetic Anisotropy ◽

Perpendicular Magnetic Anisotropy ◽

Functional Materials ◽

Spin Reorientation ◽

Amorphous Films ◽

Amorphous Thin Films ◽

Magnetic Performance ◽

Out Of Plane ◽

Sputtering Pressure

AbstractThe emergence of perpendicular magnetic anisotropy (PMA) in amorphous thin films, which eventually transforms the magnetic spins form an in-plane to the out-of-plane configuration, also known as a spin-reorientation transition (SRT), is a fundamental roadblock to attain the high flux concentration advantage of these functional materials for broadband applications. The present work is focused on unfolding the origin of PMA in amorphous thin films deposited by magnetron sputtering. The amorphous films were deposited under a broad range of sputtering pressure (1.6–6.2 mTorr), and its effect on the thin film growth mechanisms was correlated to the static global magnetic behaviours, magnetic domain structure, and dynamic magnetic performance. The films deposited under low-pressure revealed a dominant in-plane uniaxial anisotropy along with an emerging, however feeble, perpendicular component, which eventually evolved as a dominant PMA when deposited under high-pressure sputtering. This change in the nature of anisotropy redefined the orientation of spins from in-plane to out-of-plane. The SRT in amorphous films was attributed to the dramatic change in the growth mechanism of disorder atomic structure from a homogeneously dispersed to a porous columnar microstructure. We suggest the origin of PMA is associated with the columnar growth of the amorphous films, which can be eluded by a careful selection of a deposition pressure regime to avoid its detrimental effect on the soft magnetic performance. To the author’s best knowledge, no such report links the sputtering pressure as a governing mechanism of perpendicular magnetisation in technologically important amorphous thin films.

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Strain-induced perpendicular magnetic anisotropy and Gilbert damping of Tm3Fe5O12 thin films

Scientific Reports ◽

10.1038/s41598-019-53255-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Oana Ciubotariu ◽

Anna Semisalova ◽

Kilian Lenz ◽

Manfred Albrecht

Keyword(s):

Film Thickness ◽

Magnetic Anisotropy ◽

Tensile Strain ◽

Easy Axis ◽

Perpendicular Magnetic Anisotropy ◽

Gilbert Damping ◽

Sample Plane ◽

Iron Garnets ◽

Out Of Plane ◽

Magnetic Easy Axis

AbstractIn the attempt of implementing iron garnets with perpendicular magnetic anisotropy (PMA) in spintronics, the attention turned towards strain-grown iron garnets. One candidate is Tm3Fe5O12 (TmIG) which possesses an out-of-plane magnetic easy axis when grown under tensile strain. In this study, the effect of film thickness on the structural and magnetic properties of TmIG films including magnetic anisotropy, saturation magnetization, and Gilbert damping is investigated. TmIG films with thicknesses between 20 and 300 nm are epitaxially grown by pulsed laser deposition on substituted-Gd3Ga5O12(111) substrates. Structural characterization shows that films thinner than 200 nm show in-plane tensile strain, thus exhibiting PMA due to strain-induced magnetoelastic anisotropy. However, with increasing film thickness a relaxation of the unit cell is observed resulting in the rotation of the magnetic easy axis towards the sample plane due to the dominant shape anisotropy. Furthermore, the Gilbert damping parameter is found to be in the range of 0.02 ± 0.005.

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Low-field Magnetic Anisotropy of Sr2IrO4

Journal of Physics Condensed Matter ◽

10.1088/1361-648x/ac484d ◽

2022 ◽

Author(s):

Muhammad Nauman ◽

Tayyaba Hussain ◽

Joonyoung Choi ◽

Nara Lee ◽

Young Jai Choi ◽

...

Keyword(s):

Magnetic Anisotropy ◽

Exchange Interaction ◽

Exchange Interactions ◽

Orbit Coupling ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Easy Magnetization ◽

Magnetic Exchange ◽

Crystal Field Effect ◽

Out Of Plane

Abstract Magnetic anisotropy in strontium iridate (Sr2IrO4) is essential because of its strong spin–orbit coupling and crystal field effect. In this paper, we present a detailed mapping of the out-of-plane (OOP) magnetic anisotropy in Sr2IrO4 for different sample orientations using torque magnetometry measurements in the low-magnetic-field region before the isospins are completely ordered. Dominant in-plane anisotropy was identified at low fields, confirming the b axis as an easy magnetization axis. Based on the fitting analysis of the strong uniaxial magnetic anisotropy, we observed that the main anisotropic effect arises from a spin–orbit-coupled magnetic exchange interaction affecting the OOP interaction. The effect of interlayer exchange interaction results in additional anisotropic terms owing to the tilting of the isospins. The results are relevant for understanding OOP magnetic anisotropy and provide a new way to analyze the effects of spin–orbit-coupling and interlayer magnetic exchange interactions. This study provides insight into the understanding of bulk magnetic, magnetotransport, and spintronic behavior on Sr2IrO4 for future studies.

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MAGNETIC ANISOTROPY OF CoFeB AMORPHOUS NANOTUBES PREPARED BY ELECTROLESS PLATING IN MAGNETIC FIELD

Modern Physics Letters B ◽

10.1142/s0217984913410066 ◽

2013 ◽

Vol 27 (19) ◽

pp. 1341006 ◽

Cited By ~ 1

Author(s):

Z. LIU ◽

W. L. LI ◽

W. D. FEI

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

Magnetic Anisotropy ◽

Electroless Plating ◽

Applied Field ◽

Anodized Aluminum ◽

Anodized Aluminum Oxide ◽

Squareness Ratio ◽

Out Of Plane ◽

Structural And Magnetic Properties

CoFeB nanotubes were fabricated by electroless plating in magnetic field using anodized aluminum oxide template, and the structural and magnetic properties of CoFeB nanotubes were investigated. It is found that some nano-scale particles form on the wall of nanotubes. Both coercivity ratio and squareness ratio of out-of-plane to in-plane are significantly changed by the applied magnetic field during electroless plating, which indicates that directional ordering in amorphous CoFeB nanotubes are achieved during electroless plating under magnetic field. The results show that the applied field impacts the magnetic anisotropy of amorphous nanotubes. The anisotropy is stronger with the magnitude of applied field increasing.

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Pair Ordering Anisotropy In Amorphous Tb-Fe Thin Films

MRS Proceedings ◽

10.1557/proc-384-239 ◽

1995 ◽

Vol 384 ◽

Cited By ~ 1

Author(s):

T.C. Hufnagel ◽

S. Brennan ◽

B.M. Clemens

Keyword(s):

Thin Films ◽

Magnetic Anisotropy ◽

Perpendicular Magnetic Anisotropy ◽

High Energy ◽

Distribution Functions ◽

Anisotropy Energy ◽

Magnetic Anisotropy Energy ◽

Structural Anisotropy ◽

Out Of Plane ◽

Plane Direction

ABSTRACTWe have studied the structural origins of perpendicular magnetic anisotropy in amorphous Tb-Fe thin films by employing high energy x-ray scattering. The as-deposited films show a clear structural anisotropy, with a preference for Fe-Tb near-neighbors to align in the out-of-plane direction. Upon annealing, the magnetic anisotropy energy drops significantly, and we see a corresponding reduction in the structural anisotropy. The radial distribution functions indicate that the number of Fe-Tb near-neighbors increases in the in-plane direction, but does not change in the out-of-plane direction. Therefore, the distribution of Fe-Tb near-neighbors becomes more uniform upon annealing. We conclude that the observed reduction in perpendicular magnetic anisotropy energy is a result of this change in structure.

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Contribution from Ising domains overlapping out-of-plane to perpendicular magnetic anisotropy in Mn4N thin films on MgO(001)

Journal of Magnetism and Magnetic Materials ◽

10.1016/j.jmmm.2017.03.079 ◽

2017 ◽

Vol 439 ◽

pp. 236-244 ◽

Cited By ~ 2

Author(s):

Andrew Foley ◽

Joseph Corbett ◽

Alam Khan ◽

Andrea L. Richard ◽

David C. Ingram ◽

...

Keyword(s):

Thin Films ◽

Magnetic Anisotropy ◽

Perpendicular Magnetic Anisotropy ◽

Out Of Plane

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Theoretical Study of the Magnetic Anisotropy of Ni Films on Cu(001)

MRS Proceedings ◽

10.1557/proc-475-507 ◽

1997 ◽

Vol 475 ◽

Author(s):

M. Freyss ◽

R. Lorenz ◽

H. Dreysse ◽

J. Hafner

Keyword(s):

Magnetic Anisotropy ◽

Theoretical Study ◽

Magnetic Moments ◽

Tight Binding ◽

Real Space ◽

Spin Orbit Coupling ◽

Magnetization Direction ◽

Out Of Plane ◽

Lmto Method ◽

The Stability

ABSTRACTThe anisotropy properties of Ni films on Cu(001) are quite unusual compared to other systems: The magnetization direction of Ni is in-plane for a coverage smaller than a critical thickness of 7 monolayers and out-of-plane for a coverage larger than 7 monolayers. As a first step in the study of this unusual behaviour, we report results of ab-initio calculations of the magnetic order of Ni films on a Cu(001) substrate. The magnetic moments are computed by means of the real-space Tight-Binding LMTO method allowing non-collinear magnetic moments and including spin-orbit coupling to account for magnetic anisotropy effects. As the number of Ni layers is increased, we discuss the stability of the system with a magnetization in-plane or out-of-plane.

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Thickness Dependent Perpendicular Magnetic Domain Patterns in Sputtered Epitaxial FePt (001) L10 Films

MRS Proceedings ◽

10.1557/proc-517-319 ◽

1998 ◽

Vol 517 ◽

Cited By ~ 4

Author(s):

J.-U. Thiele ◽

L. Folks ◽

M. F. Toney ◽

D. K. Weller

Keyword(s):

Magnetic Anisotropy ◽

Magnetic Domain ◽

Perpendicular Magnetic Anisotropy ◽

Grazing Incidence ◽

Anisotropy Constant ◽

Exchange Constant ◽

Stripe Domain ◽

Chemical Ordering ◽

Out Of Plane ◽

Face Centered

AbstractThe present paper discusses the magnetic anisotropy and magnetic domain structure of highly ordered epitaxial FePt(001) films grown on Pt seeded MgO(001) substrates. These films were grown by dc-magnetron sputtering from a Fe50Pt50 alloy target at a substrate temperature of 550°C during deposition. Thicknesses were varied between 15 and 170 nm. The presence of the highly anisotropic face centered tetragonal L10 crystal structure with a maximum long range chemical ordering of 95% and a low degree of misorientations was confirmed by specular and grazing incidence X-ray diffraction measurements. For film thicknesses ≥ 50 nm in-plane and out-of-plane hysteresis measurements indicate large perpendicular magnetic anisotropy and at the same time low remanent magnetisation. Magnetic force microscopy reveals highly interconnected perpendicular stripe domain patterns. From their characteristic width, which is strongly dependent on the film thickness, a value of the dipolar length, D0, of 50 ±5 nm is derived. Assuming an exchange constant of 10-6 erg/cm, this value is consistent with an anisotropy constant Ku ∼ 1.108 erg/cc.

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Interfacial coupling effect of Cr2O3 on the magnetic properties of Fe72Ga28 thin films

Scientific Reports ◽

10.1038/s41598-021-92640-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

I. Hontecillas ◽

M. Maicas ◽

J. P. Andrés ◽

R. Ranchal

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

Magnetic Anisotropy ◽

Coupling Effect ◽

Perpendicular Magnetic Anisotropy ◽

Interfacial Coupling ◽

Bias Effect ◽

Exchange Bias Effect ◽

Sample Plane ◽

Out Of Plane

AbstractHere it is investigated the effect of the antiferromagnet Cr2O3 on the magnetic properties of ferromagnetic Fe72Ga28 thin films. Sputtered Fe72Ga28 layers have their magnetization in the sample plane with a magnetic fluctuation that gives rise to magnetic ripple. In order to turn its magnetization into the out of plane (OOP) direction, it has been magnetically coupled with Cr2O3 that has magnetic moments along the c-axis, that is the perpendicular direction when properly aligned. Cr2O3 has been obtained from Cr oxidation, whereas Fe72Ga28 has been deposited on top of it by sputtering in the ballistic regime. Although a uniaxial in-plane magnetic anisotropy is expected for Fe72Ga28 thickness above 100 nm, the interfacial coupling with Cr2O3 prevents this anisotropy. The formation of stripe domains in Fe72Ga28 above a critical thickness reveals the enhancement of the out of plane component of the Fe72Ga28 magnetization with respect to uncoupled layers. Due to the interface coupling, the Fe72Ga28 magnetization turns into the out-of-plane direction as its thickness is gradually reduced, and a perpendicular magnetic anisotropy of 3·106 erg·cm−3 is inferred from experimental results. Eventually, the coupling between Cr2O3 and Fe72Ga28 promotes an exchange-bias effect that has been well fitted by means of the random field model.

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