SPICE Workshop on Nanomagnetism in 3D, April 30th - May 2nd 2024
Benjamin Jungfleisch
As the carbon footprint and associated energy costs of traditional computing platforms continue to increase, finding alternative, more efficient computational architectures, is imperative. Magnonic systems based on the elementary quanta of spin waves – magnons, offer a potential solution. However, before we can create efficient magnonic computing elements, we need to understand how to control magnons at the nanoscale effectively. This can be achieved by strongly interacting artificial spin ice (ASI) systems, which are magnetic metamaterials where magnetic domains can be mapped onto a spin-lattice model [1]. These systems have recently emerged as functional material platforms for reconfigurable magnonics, including two-dimensional magnonic crystals, in which the desired magnon band structure is engineered, similar to the approach taken in photonics.
Here, we couple square ASI structures made of CoFeB or NiFe stadium-shaped nanoelements to continuous NiFe film underlayers to understand how the presence of the ASI affects the spin-wave properties in the film underlayer. We present a combined experimental and numerical study of the spin-wave dispersion in the ASI/film hybrid structures [2,3]. The spin-wave dispersion, measured by wavevector resolved Brillouin light scattering spectroscopy, consists of a rich number of modes with either stationary or propagating character [3]. Micromagnetic simulations unveil the details of the dynamic coupling between the ASI lattice and film underlayer. The ASI lattice facilitates dynamics of the film, either specific wavelengths or intensity modulation peculiar to the modes of the ASI elements imprinted in the film. Our results demonstrate that propagating spin waves can be modulated at the nanometer length scale by harnessing the dynamic mode coupling in the vertical, i.e., the out-of-plane direction of suitably designed structures. These findings also directly benefit our understanding of magnon-magnon interactions in three-dimensional multilayered artificial spin-ice systems [4].
Work on the NiFe ASI/NiFe film systems was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-SC0020308. It was partially supported by NSF through ENG-1839056. Research on the CoFeB ASI/NiFe film systems was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC-0024346. G.G. acknowledges the European Union - NextGenerationEU under the Italian Ministry of University and Research (MUR) National Innovation Ecosystem grant ECS00000041 – VITALITY. CUP: B43C22000470005. This project received funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 101007417, having benefited from IOM-CNR access within the framework of the NFFA-Europe Pilot Transnational Access Activity, Proposal No. ID151. F.M. acknowledges the CINECA award under the ISCRA initiative, for the availability of high performance computing resources and support (Project SWIM-3D on Leonardo).
References
1. Kaffash, M. T., Lendinez, S., and Jungfleisch, M. B., Phys. Lett. A 402, 127364, (2021).
2. Montoncello, F., Kaffash, M. T., Carfagno, H., Doty, M. F., Gubbiotti, G., and Jungfleisch, M. B., J. Appl. Phys. 133, 083901 (2023).
3. Negrello, R., Montoncello, F., Kaffash, M. T., Jungfleisch, M. B., and Gubbiotti, G., APL Mater. 10, 091115, (2022).
4. Dion, T., Stenning, K. D., Vanstone, A., Holder, H. H., Sultana, R., Alatteili, G., Martinez, V., Kaffash, M. T., Kimura, T., Oulton, R., Kurebayashi, H., Branford, W. R., Iacocca, E., Jungfleisch, M. B., and Gartside, J. C., https://doi.org/10.48550/arXiv.2306.16159