Telecommunications beyond 6G: the first standalone spin-wave chip with a built-in magnetic field

Milan, 13^th January 2025  - The Politecnico di Milano has created the first integrated and fully tunable device based on spin waves, opening up new possibilities for the telecommunications of the future, far beyond current 5G and 6G standards. The study, published in the journal Advanced Materials, was conducted by a research group led by Riccardo Bertacco of the Department of Physics of the Politecnico di Milano, in collaboration with Philipp Pirro of Rheinland-Pfälzische Technische Universität and Silvia Tacchi of Istituto Officina dei Materiali - CNR-IOM.

Magnonics is an emerging technology that uses spin waves – collective excitations of electronic spins in magnetic materials – as an alternative to electrical signals. The spread of this technology has been restricted until now by the need for an external magnetic field, which has prevented it being incorporated into chips.

The new device developed at the Politecnico overcomes this hurdle: it is miniaturised (100 × 150 square micrometres, so much smaller than current radiofrequency signal processing devices based on acoustic waves); it is fully integrated on silicon – and therefore compatible with existing electronic platforms, and it functions without external magnets, thanks to an innovative combination of permanent SmCo micromagnets and magnetic flux concentrators.

The spin wave guide is made of CoFeB and fitted with two antennas for the input and output of the RF signal. The transverse magnetic field can be modulated very precisely by varying the distance between the magnets and concentrators to between 11 and 20.5 mT. This enables the operating frequency to be adjusted to between 3 and 8 GHz, and the phase shift to be tuned up to 120 degrees at 6 GHz.

As well as demonstrating the principle of the technology, the researchers point out that the prototypes are already functioning as time delay lines and phase shifters, without the application of an external bias field; that the design could be incorporated with MEMS to allow the devices to be reconfigured in real time; and that the choice of SmCo micromagnets ensures they will remain stable in temperatures of up to 200°C and can generate the magnetic field without consuming energy.

As Riccardo Bertacco of the Department of Physics of the Politecnico di Milano has explained: "This result is a decisive step towards moving spin waves from demonstrations in the lab towards a technology that can actually be incorporated into telecommunication systems and electronic circuits."

Silvia Tacchi, from CNR-IOM, adds: "This finding represents a key advancement in the field of magnonics, bringing spin-wave chips closer to being integrated into electronic devices".

The development of these devices is part of the MandMEMS project, funded by the European Union in the context of Horizon Europe. The coordinator of the project, Philipp Pirro from RPTU, incorporates this success into the project roadmap: “Building on this milestone, we can now tackle the next challenges, such as further increasing the transmission efficiency of the devices. Based on the large improvements achieved up to date, we are confident to present soon marketable devices for 6G which are based on standalone spin-wave chips”. 

The consortium involves various European research centres and industrial partners, with expertise ranging from magnonics to MEMS, and RF electronics to materials science. The aim is to develop a technological platform that can make the communication devices of the future more efficient, compact and reconfigurable, paving the way for new applications in telecommunications and high-frequency electronics.

With this innovation, the Politecnico di Milano, Rheinland-Pfälzische Technische Universität and  Istituto Officina dei Materiali - CNR-IOM have prepared the ground for compact, low-power, high-performance devices, with possible repercussions not only for future telecommunications, but also for consumer electronics, the automotive sector, diagnostics, and more generally for all applications that require integrated processing of high-frequency signals.

Website of the project: www.mandmems.eu

M. Cocconcelli, F. Maspero, A. Micelli, A. Toniato, A. Del Giacco, N. Pellizzi, A. E. Plaza, A. Cattoni, M. Madami, R. Silvani, C. Adelmann, A. A. Hamadeh, P. Pirro, S. Tacchi, F. Ciubotaru, R. Bertacco, Standalone Integrated Magnonic Devices. Adv. Mater. 2025, 2503493. https://doi.org/10.1002/adma.202503493