Dr. Kilian Lenz

Research Group Head
Phone: +49 351 260 2435
Fax: +49 351 260 12435

Spin Wave Excitations in Periodic Nanostructures: Transition from Periodical Perturbations to Magnonic Crystals

funded by DFG: LE 2443/5-1




  • Prof. Dr. Pedro Landeros (UTFSM Valparaíso, Chile)
  • Rodolfo A. Gallardo (UTFSM Valparaíso, Chile)


The main objective of the project is to investigate the spin wave dynamics in the transition regime from a flat film with periodical nanostructures on top towards a full 1D or 2D magnonic crystal. This regime exhibits the beginning of the mode splitting due to the two-magnon interaction, which in magnonic crystals finally lead to the opening of band gaps. Compared to studies on full magnonic crystals no attention has been paid to this important transition regime so far.

Experimental techniques like broadband ferromagnetic resonance, time-resolved magnetooptical Kerr effect as well as Brillouin light scattering will be employed to study the magnon excitations in those nanostructures. In close collaboration with the theory group of Prof. P. Landeros (UTFSM Chile) already existing analytical theory will be applied and further developed to match and explain the experimental findings, e.g. descriptions and meaning of the individual modes, understanding of the development of the avoided band crossing, as well as insight into enhanced damping effects in such structures.

Editors' suggestion:
Spin-wave modes in transition from a thin film to a full magnonic crystal

Multistep Etching Teaser from PRB ©Copyright: Manuel Langer
Standing spin waves in thin films with a tiny periodic surface modulation are quantized in such a way that a multiple of their wavelength fits into one modulation period. This paper tackles the question how these film modes evolve into modes in a one-dimensional magnonic crystal consisting of periodic individual wire structures. By sequentially increasing the surface modulation and subsequent dynamic characterization of the same sample, simple transition rules are found connecting the modes of both systems with one another.
M. Langer et al. Phys. Rev. B 99, 024426 (2019)


  • Spin-Wave Modes in Transition from a Thin Film to a Full Magnonic Crystal
    M. Langer, R. A. Gallardo, T. Schneider, S. Stienen, A. Roldán-Molina, Y. Yuan, K. Lenz, J. Lindner, P. Landeros, J. Fassbender
    Phys. Rev. B 99, 024426 (2019)
  • Symmetries and localization properties of defect modes in metamaterial magnonic superlattices
    R. A. Gallardo, T. Schneider, A. Roldán-Molina, M. Langer, A. S. Núñez, K. Lenz, J. Lindner, P. Landeros
    Phys. Rev. B 97, 174404 (2018)
  • Dipolar interaction induced band gaps and flat modes in surface-modulated magnonic crystals
    R. A. Gallardo, T. Schneider, A. Roldan-Molina, M. Langer, J. Fassbender, K. Lenz, J. Lindner, P. Landeros
    Phys. Rev. B 97,144405 (2018)
  • Role of the internal demagnetizing field for the dynamics of a surface-modulated magnonic crystal
    M. Langer, F. Röder, R. A. Gallardo, T. Schneider, S. Stienen, C. Gatel, R. Hübner, L. Bischoff, K. Lenz, J. Lindner, P. Landeros, J. Fassbender
    Phys. Rev. B 95, 184405 (2017)
  • Parameter-free determination of the exchange constant in thin films using magnonic patterning
    M. Langer, K. Wagner, T. Sebastian, R. Hübner, J. Grenzer, Y. Wang, T. Kubota, T. Schneider, S. Stienen, J. Linder, K. Lenz, J. Linder, K. Takanashi, R. Arias, J. Fassender
    Appl. Phys. Lett. 108, 102402 (2016)
  • Splitting of spin-wave modes in thin films with arrays of periodic perturbations: theory and experiment
    R. A. Gallardo, K. Lenz, A. Banholzer, M. Körner, J. Lindner, J. Fassbender, and P. Landeros
    J. Phys.: Condens. Matter., in print (2014)
  • Frequency dependence of spin relaxation in periodic systems
    I. Barsukov, F. M. Römer, R. Meckenstock, K. Lenz, J. Lindner, S. Hemken to Krax, A. Banholzer, M. Körner, J. Grebing, J. Fassbender, and M. Farle
    Phys. Rev B. 84, 140410(R) (2011)