Department of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy
Prof. Federico Montoncello

Date, Time
29.01, 15:00 - 16:00

Affiliation
Department of Physics and Earth Sciences, Univeristy of Ferrara, Itlay

Abstract
In Magnonics, the combination of layers with different geometric patterns offers a variety of dynamic degrees of freedom for magnon control at the nanoscale, leading to versatile, miniaturized and extremely low dissipation devices for information transport and manipulation. In the first part of the talk, we show by micromagnetic simulations and experimental evidence how, when an artificial spin ice (ASI) layer is brought close to a film layer, a frequency selective magnon-magnon interaction arises between the film spin wave and the ASI modes [1]. The ASI modes which are involved (either edge or bulk) can be selected by the choice of the materials, mainly based on the saturation magnetization values [2]. In the second part, we discuss the case of a straight film layer with an undulated, periodic magnetization distribution determined by the interaction with a likewise undulated magnetic field: this field can be created either directly by a meandering conductor, or a magnetic material with undulated pattern, or most interestingly by inverse magnetostriction operated by a coupled ferroelectric layer with a periodic polarization direction [3]. The result is a dynamic magnonic crystal displaying a magnonic band structure, with a frequency gap and a dispersion curvature which can be finely tuned by varying either the magnitude or fan angle of magnetic field created by the meander, or even by the electric field applied on the ferroelectric layer, which we simulate through a variable uniaxial magnetic anisotropy [4]. We discuss the transition between a magnonic metal state, interpreted within the Dirac’s magnon picture, and an insulator state, with a controllable frequency gap position and width, which is found particularly useful in the context of magnon transport in directional couplers.

[1] Negrello, R.; Montoncello, F.; Kaffash, M. T.; Jungfleisch, M. B.; Gubbiotti, G. Dynamic coupling and spin-wave dispersions in a magnetic hybrid system made of an artificial spin-ice structure and an extended NiFe underlayer. APL Materials 10, 091115 (2022).

[2] Rawnak Sultana, Mojtaba Taghipour Kaffash, Gianluca Gubbiotti, Yi Ji, M. Benjamin Jungfleisch, Federico Montoncello Magnon-Magnon Interaction Induced by Dynamic Coupling in a Hybrid Magnonic Crystal. https://arxiv.org/abs/2510.06004 (ACS Applied Electronic Materials, accepted manuscript).

[3] P. Micaletti, A. Roxburgh, E. Iacocca, M. Marzolla, and F. Montoncello A sinusoidal magnetization distribution as an original way to generate a versatile magnonic crystal for magnon propagation. Journal of Magnetism and Magnetic Materials 622, 172959 (2025).

[4] Pietro Micaletti, Alison Roxburgh, Ezio Iacocca, Moreno Marzolla, and Federico Montoncello. Magnonic analog of a metal-to-insulator transition in a multiferroic heterostructure. Journal of Applied Physics 137, 153906 (2025).