Contact

Porträt Dr. Kakay, Attila; FWIN-C

Dr. Attila Kakay

Head
Micromagnetic Modeling group leader
a.kakayAthzdr.de
Phone: +49 351 260 3410

Micromagnetic Modeling


Recent progress in material science has enabled the first experimental studies concerning the static magnetization characterization of samples with tubular geometry, such as rolled-up structures, nanowires and nanotubes. The bending of a flat thin-film to a curved surface introduces a break of the local inversion symmetry and can lead to surprising phenomena which do not unfold in flat geometries. As an example, domain walls in nanotubes  show a chiral symmetry breaking regarding their propagation and moreover can propagate so fast that can trigger a  Cherenkov-type spin-wave radiation. A further example is that this lack of inversion symmetry leads to an asymmetric dispersion relation for the spin waves regarding the sign of the propagation vector. This is a purely curvature induced effect with its origin in the classical dipole-dipole interaction. 

Using finite element micromagnetic simulations with our in-house developed program TetraMag (originally developed by Dr. Riccardo Hertel), we study the effect of the surface curvature on the statics and dynamics of typical spin textures as well as on the spin-wave propagation. The usual spin textures are domain walls, vorticies, Bloch points and Skyrmions formed in ferromagnetic nanowires and nanotubes. Although investigating spin-wave and domain-wall dynamics is still a challenge from experimental point of view, a combined effort of the experimental groups in our devision helps to confirm the results predicted by simulations.

Besides the basic research we develop GPU accelerated micromagnetic codes used in our studies for the finite discretisation as well as for the finite element methods and all related programs required for the analysis of the simulations. 

Research Topics

  • Spin textures in curved geometries
  • Spin-wave propagation in curved nano-membranes
  • GPU accelerated micromagnetic code development

Research Projects

  • DFG: 3D transport of spin waves in curved nano-membranes
  • DACH: Curvature-induced effects in magnetic nanostructures, in collaboration with:
    • Prof. M. Huth, Goethe Universität, Frankfurth am Main
    • Dr. Denys Makarov, HZDR
    • Dr. Oleksandr Dobrovolskiy, Universotät Wien
  • DAAD: Influence of curvature and topology on spin-wave transport
    • Bilateral Exchange of Academics with Chile, Dr. J. A. Otálora from Universidad Católica del Norte 

Acknowledgments

We are grateful to Henrik Schulz and Jens Lasch for their continuous support of our computational infrastructure.


Recent publications

Full list availabe here.

2022

Finite-element dynamic-matrix approach for propagating spin waves: Extension to mono- and multilayers of arbitrary spacing and thickness

Körber, L.; Hempel, A.; Otto, A.; Gallardo, R. A.; Henry, Y.; Lindner, J.; Kakay, A.


Curvilinear spin-wave dynamics beyond the thin-shell approximation: Magnetic nanotubes as a case study

Körber, L.; Verba, R.; Otálora, J. A.; Kravchuk, V.; Lindner, J.; Faßbender, J.; Kakay, A.

Downloads


Mode splitting of spin waves in magnetic nanotubes with discrete symmetries

Körber, L.; Kézsmárki, I.; Kakay, A.

Downloads


Curvature-induced drift and deformation of magnetic skyrmions: Comparison of the ferromagnetic and antiferromagnetic cases

Yershov, K.; Kakay, A.; Kravchuk, V. P.

Downloads


New dimension in magnetism and superconductivity: 3D and curvilinear nano-architectures

Makarov, D.; Volkov, O.; Kakay, A.; Pylypovskyi, O.; Budinska, B.; Dobrovolskiy, O.

Related publications


Spin-wave frequency combs

Hula, T.; Schultheiß, K.; Trindade Goncalves, F. J.; Körber, L.; Bejarano, M.; Copus, M.; Flacke, L.; Liensberger, L.; Buzdakov, A.; Kakay, A.; Weiler, M.; Camley, R.; Faßbender, J.; Schultheiß, H.

Downloads


2021

Spin-wave focusing induced by dipole-dipole interaction in synthetic antiferromagnets

Gallardo, R. A.; Alvarado-Seguel, P.; Kákay, A.; Lindner, J.; Landeros, P.

Downloads

  • Secondary publication expected

Robust formation of nanoscale magnetic skyrmions in easy-plane anisotropy thin film multilayers with low damping

Flacke, L.; Ahrens, V.; Mendisch, S.; Körber, L.; Böttcher, T.; Meidinger, E.; Yaqoob, M.; Müller, M.; Liensberger, L.; Kakay, A.; Becherer, M.; Pirro, P.; Althammer, M.; Geprägs, S.; Huebl, H.; Gross, R.; Weiler, M.

Downloads


Symmetry and curvature effects on spin waves in vortex-state hexagonal nanotubes

Körber, L.; Zimmermann, M.; Wintz, S.; Finizio, S.; Kronseder, M.; Bougeard, D.; Dirnberger, F.; Weigand, M.; Raabe, J.; Otálora, J. A.; Schultheiß, H.; Josten, E.; Lindner, J.; Kézsmárki, I.; Back, C. H.; Kakay, A.

Downloads


Numerical reverse engineering of general spin-wave dispersions: Bridge between numerics and analytics using a dynamic-matrix approach

Körber, L.; Kakay, A.

Downloads


Stress-induced modification of gyration dynamics in stacked double-vortex structures studied by micromagnetic simulations

Iurchuk, V.; Körber, L.; Deac, A. M.; Faßbender, J.; Lindner, J.; Kakay, A.


Nonreciprocity of spin waves in magnetic nanotubes with helical equilibrium magnetization

Salazar-Cardona, M. M.; Körber, L.; Schultheiß, H.; Lenz, K.; Thomas, A.; Nielsch, K.; Kakay, A.; Otálora, J. A.

Downloads


Multistate current-induced magnetization switching in Au/Fe/MgO(001) epitaxial heterostructures

Gospodarič, P.; Młyńczak, E.; Soldatov, I.; Kakay, A.; Bürgler, D. E.; Plucinski, L.; Schäfer, R.; Faßbender, J.; Schneider, C. M.


Finite-element dynamic-matrix approach for spin-wave dispersions in magnonic waveguides with arbitrary cross section

Körber, L.; Quasebarth, G.; Otto, A.; Kakay, A.


Theory of three-magnon interaction in a vortex-state magnetic nanodot

Verba, R.; Körber, L.; Schultheiß, K.; Schultheiß, H.; Tiberkevich, V.; Slavin, A.

Downloads


Spin-wave dynamics and symmetry breaking in an artificial spin ice

Saha, S.; Zhou, J.; Hofhuis, K.; Kakay, A.; Scagnoli, V.; Heyderman, L. J.; Gliga, S.

Downloads


Time refraction of spin waves

Schultheiß, K.; Sato, N.; Matthies, P.; Körber, L.; Wagner, K.; Hula, T.; Gladii, O.; Pearson, J. E.; Hoffmann, A.; Helm, M.; Faßbender, J.; Schultheiß, H.

Downloads


Numerical ferromagnetic resonance experiments in nanosized elements

Wagner, K.; Körber, L.; Stienen, S.; Lindner, J.; Farle, M.; Kakay, A.

Downloads


Self-stabilizing exchange-mediated spin transport

Schneider, T.; Hill, D.; Kakay, A.; Lenz, K.; Lindner, J.; Faßbender, J.; Upadhyaya, P.; Liu, Y.; Wang, K.; Tserkovnyak, Y.; Krivorotov, I. N.; Barsukov, I.

Related publications

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2020

Spin-transfer dynamics in MgO-based magnetic tunnel junctions with an out-of-plane magnetized free layer and an in-plane polarizer

Kowalska, E.; Sluka, V.; Kakay, A.; Fowley, C.; Lindner, J.; Fassbender, J.; Deac, A. M.

Downloads


Propagation of spin waves through a Néel domain wall

Wojewoda, O.; Hula, T.; Flajšman, L.; Vaňatka, M.; Gloss, J.; Holobrádek, J.; Staňo, M.; Stienen, S.; Körber, L.; Schultheiß, K.; Schmid, M.; Schultheiß, H.; Urbánek, M.


Effect of curvature on the eigenstates of magnetic skyrmions

Korniienko, A.; Kakay, A.; Sheka, D. D.; Kravchuk, V. P.

Downloads


Nonlocal stimulation of three-magnon splitting in a magnetic vortex

Körber, L.; Schultheiß, K.; Hula, T.; Verba, R.; Faßbender, J.; Kakay, A.; Schultheiß, H.

Downloads


Nonlinear losses in magnon transport due to four-magnon scattering

Hula, T.; Schultheiß, K.; Buzdakov, A.; Körber, L.; Bejarano, M.; Flacke, L.; Liensberger, L.; Weiler, M.; Shaw, J. M.; Nembach, H. T.; Faßbender, J.; Schultheiß, H.

Downloads


Visualizing Magnetic Structure in 3D Nanoscale Ni–Fe Gyroid Networks

Llandro, J.; Love, D. M.; Kovács, A.; Caron, J.; Vyas, K. N.; Kakay, A.; Salikhov, R.; Lenz, K.; Faßbender, J.; Scherer, M. R. J.; Cimorra, C.; Steiner, U.; Barnes, C. H. W.; Dunin-Borkowski, R. E.; Fukami, S.; Ohno, H.

Downloads


Tunable magnetic vortex dynamics in ion-implanted permalloy disks

Ramasubramanian, L.; Kákay, A.; Fowley, C.; Yildirim, O.; Matthes, P.; Sorokin, S.; Titova, A.; Hilliard, D.; Böttger, R.; Hübner, R.; Gemming, S.; Schulz, S. E.; Kronast, F.; Makarov, D.; Faßbender, J.; Deac, A. M.

Related publications

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Nonlocal chiral symmetry breaking in curvilinear magnetic shells

Sheka, D. D.; Pylypovskyi, O.; Landeros, P.; Gaididei, Y.; Kakay, A.; Makarov, D.


Domain wall-based spin-Hall nano-oscillators

Sato, N.; Schultheiß, K.; Körber, L.; Puwenberg, N.; Mühl, T.; Awad, A. A.; Arekapudi, S. S. P. K.; Hellwig, O.; Faßbender, J.; Schultheiß, H.

Related publications

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2019

Experimental Observation of Exchange-Driven Chiral Effects in Curvilinear Magnetism

Volkov, O.; Kakay, A.; Florian, K.; Mönch, J. I.; Mohamad-Assaad, M.; Faßbender, J.; Makarov, D.

Related publications

Downloads

  • Secondary publication expected

Strain Anisotropy and Magnetic Domains in Embedded Nanomagnets

Nord, M.; Semisalova, A.; Kákay, A.; Hlawacek, G.; Maclaren, I.; Liersch, V.; Volkov, O.; Makarov, D.; Paterson, G. W.; Potzger, K.; Lindner, J.; Faßbender, J.; Mcgrouther, D.; Bali, R.

Related publications


Defect-Driven Magnetization Configuration of Isolated Linear Assemblies of Iron Oxide Nanoparticles

Rastei, M. V.; Pierron-Bohnes, V.; Toulemon, D.; Bouillet, C.; Kákay, A.; Hertel, R.; Tetsi, E.; Begin-Colin, S.; Pichon, B. P.

Downloads


Magnetization Dynamics of an Individual Single-Crystalline Fe-Filled Carbon Nanotube

Lenz, K.; Narkowicz, R.; Wagner, K.; Reiche, C. F.; Körner, J.; Schneider, T.; Kákay, A.; Schultheiss, H.; Suter, D.; Büchner, B.; Fassbender, J.; Mühl, T.; Lindner, J.

Related publications


Zero-field dynamics stabilized by in-plane shape anisotropy in MgO-based spin-torque oscillators

Kowalska, E.; Kákay, A.; Fowley, C.; Sluka, V.; Lindner, J.; Fassbender, J.; Deac, A. M.

Downloads


Excitation of whispering gallery magnons in a magnetic vortex

Schultheiss, K.; Verba, R.; Wehrmann, F.; Wagner, K.; Körber, L.; Hula, T.; Hache, T.; Kákay, A.; Awad, A. A.; Tiberkevich, V.; Slavin, A. N.; Fassbender, J.; Schultheiss, H.

Related publications

  • Open Access Logo Physical Review Letters 122(2019), 097202
    Cited 37 times in Scopus
  • Invited lecture (Conferences)
    International Conference on Magnetism, 19.07.2018, San Francisco, USA
  • Invited lecture (Conferences)
    APS March Meeting, 04.03.2019, Boston, USA
  • Poster
    Wilhelm und Else Heraeus-Seminar “Spin Based Information Processing”, 08.01.2019, Bad Honnef, Deutschland
  • Lecture (Conference)
    Joint European Magnetic Symposia (JEMS), 04.09.2018, Mainz, Deutschland
  • Poster
    Magnonics 2019, 28.07.2019, Carovigno, Italien
  • Invited lecture (Conferences)
    Magnetics and Optics Research International Symposium, 24.06.2019, Prague, Czech Republic
  • Invited lecture (Conferences)
    Conference on Magnetism and Magnetic Materials (MMM), 06.11.2019, Las Vegas, USA

Downloads


Experimental and Theoretical Study of Curvature Effects in Parabolic Nanostripes

Volkov, O. M.; Kronast, F.; Mönch, I.; Mawass, M.-A.; Kákay, A.; Fassbender, J.; Makarov, D.

Related publications


Tunnel magnetoresistance angular and bias dependence enabling tuneable wireless communication

Kowalska, E.; Fukushima, A.; Sluka, V.; Fowley, C.; Kákay, A.; Aleksandrov, Y.; Lindner, J.; Fassbender, J.; Yuasa, S.; Deac, A. M.


Emission and Propagation of Multi-Dimensional Spin Waves in Anisotropic Spin Textures

Sluka, V.; Schneider, T.; Gallardo, R. A.; Kakay, A.; Weigand, M.; Warnatz, T.; Mattheis, R.; Roldan-Molina, A.; Landeros, P.; Tiberkevich, V.; Slavin, A.; Schütz, G.; Erbe, A.; Deac, A. M.; Lindner, J.; Faßbender, J.; Raabe, J.; Wintz, S.

Related publications

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2018

Frequency linewidth and decay length of spin waves in curved magnetic membranes

Otalora, J. A.; Kákay, A.; Lindner, J.; Schultheiss, H.; Thomas, A.; Fassbender, J.; Nielsch, K.

Downloads


Origin and Manipulation of Stable Vortex Ground States in Permalloy Nanotubes

Zimmermann, M.; Gerhard-Meier, T. N.; Dirnberger, F.; Kákay, A.; Decker, M.; Wintz, S.; Finizio, S.; Josten, E.; Raabe, J.; Kronseder, M.; Bougeard, D.; Lindner, J.; Back, C. H.

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Multiplet of skyrmion states on a curvilinear defect: Reconfigurable skyrmion lattices

Kravchuk, V. P.; Sheka, D. D.; Kákay, A.; Volkov, O. M.; Rößler, U. K.; van den Brink, J.; Makarov, D.; Gaididei, Y.

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Contact

Dr. Attila Kakay

Head
Micromagnetic Modeling group leader
a.kakayAthzdr.de
Phone: +49 351 260 3410