On February 23, 2026, at 1:15 PM, in room 2011 of the Faculty of Physics, University of Białystok, Mr. Mathieu Moalic, M.Sc., from the Faculty of Physics and Astronomy, Institute of Spintronics and Quantum Information, Adam Mickiewicz University in Poznań,will give a lecture entitled:
„Numerical Investigations of Collective Spin-Wave Dynamics in Complex Magnetic Textures and Patterned Ferromagnetic Films”
Andrzej Maziewski
Jerzy Przeszowski
„Numerical Investigations of Collective Spin-Wave Dynamics in Complex Magnetic Textures and Patterned Ferromagnetic Films”
Mathieu Moalic
Faculty of Physics and Astronomy, Institute of Spintronics and Quantum Information,Adam Mickiewicz University, Poznań
Spin waves (magnons) offer an energy-efficient alternative to charge-based electronics: they can transport and process information with very low dissipation, and at microwave frequencies their wavelengths can reach the sub-300-nm scale, enabling compact nanoscale components. A central challenge for practical magnonic circuitry is achieving deterministic control over spin-wave spectra, spatial mode profiles, and interactions between functional elements on sub-micrometre length scales. In this thesis, I establish design rules and numerical tools for programmable control of spin waves in patterned ferromagnetic thin films. I also present two open-source software packages developed during this work: the micromagnetic simulator Amumax and the post-processing toolkit Pyzfn, designed for space- and time-efficient analysis of large micromagnetic datasets. The research results are organised around three complementary control knobs—anisotropy, geometry, and nonlinearity—implemented in lithography-friendly thin-film platforms. First, I show that anisotropy engineering in perpendicular-anisotropy films patterned with antidots and softened rims enables reconfigurable spectra, including rim-localised edge modes, edge–bulk hybridisation, magnonic bandgaps, and history-dependent non-reciprocity. Building on these textured states, I demonstrate strong exchange-mediated magnon–magnon coupling between confined and propagating modes, tunable by field magnitude and magnetic history. Next, I exploit nonlinear dynamics in a simple hybrid architecture to generate coherent propagating exchange-dominated spin waves via efficient second-harmonic conversion, producing sub-300-nm wavelengths with a field- and geometry-tunable output. Then, I investigate hierarchical confinement in deterministic Sierpiński-triangle magnonic fractals, yielding geometrically and field-rotation-tunable minibands and bandgaps. I finally report experimental validation of bandgaps and defect cavities in a low-loss 1D YIG hole-based magnonic nanocrystal. Together, these results provide a practical framework for programmable magnonics with controllable spectra, interactions, and on-chip frequency conversion. References M. Moalic, M. Krawczyk, M. Zelent, "Spin-wave spectra in antidot lattice with inhomogeneous perpendicular magnetic anisotropy," Journal of Applied Physics 132(21), 213901 (2022). M. Moalic, M. Zelent, K. Szulc, M. Krawczyk, "The role of non-uniform magnetisation texture for magnon-magnon coupling in an antidot lattice," Scientific Reports 14(1), 11501 (2024). M. Moalic, Y. Patat, M. Zelent, M. Krawczyk, "Efficient generation of second-harmonic propagating spin waves in a thin, out-of-plane-magnetised ferromagnetic film," arXiv preprint 2509.07705 (2025). R. Mehta, M. Moalic, M. Krawczyk, S. Saha, "Tunability of spin-wave spectra in a 2D triangular shaped magnonic fractals," Journal of Physics: Condensed Matter 35(32), 324002 (2023). K. O. Levchenko et al., "1D YIG hole-based magnonic nanocrystal," Applied Physics Letters 127, 172401 (2025). Software (open source) Amumax (micromagnetic simulations): https://github.com/mathieumoalic/amumax Pyzfn (post-processing/analysis): https://github.com/mathieumoalic/pyzfn.
