arXiv subjects

Maria Cocconcelli

Publications and source records attributed to Maria Cocconcelli.

6 recordsLinked to original sources

arXiv2026

Integrated tunable magnonic devices for beyond 6 GHz signal processing

In the search for novel technology platforms supporting the transition towards ''beyond 6G'' telecommunications, magnonics is emerging as a viable route, primarily due to its intrinsic compatibility with the UWB-FR3 bands and its easy tunability. In this paper, we present a proof-of-concept device based on a CoFeB magnonic waveguide, fully integrated on silicon, which demonstrates all the key features of our integration approach, based on co-integrated hard magnetic micromagnets, magnonic conduits, reconfigurable soft magnetic elements and MEMS. The bias field enabling operation up to about 12 GHz is provided by SmCo micromagnets embedded in the silicon substrate. Real-time tunability is implemented in two ways. First, current-driven control is achieved via an integrated current line that generates an additional localized magnetic field, enabling continuous tuning of Backward Volume spin-wave propagation. Second, we achieve voltage-controlled tunability by integrating a NiFeMo soft magnetic element onto a piezoelectric MEMS cantilever and flip-chipping it onto the magnonic device. Upon actuation, the cantilever brings the NiFeMo into proximity with the permanent micromagnets, where it captures the stray field. The resulting voltage-controlled displacement modulates the coupling between the hard and soft magnetic components, effectively reducing the local bias field on the CoFeB waveguide and enabling fine control of Damon--Eshbach spin waves.

physics.app-ph↗

arXiv2026

Microscaled Tunable Magnonic RF Phase Shifters

Tunable, microscopic, and energy-efficient solutions for radio-frequency (RF) signal manipulation in the GHz regime are a key technology for efficient communication and sensing applications. Spin waves offer micrometer wavelengths at GHz frequencies, combined with strong magnetic-field tunability, making them inherently well-suited for tunable analog signal processing. Here, we demonstrate a novel concept: a micron-scale tunable RF phase shifter based on the wavelength shift of propagating spin waves. High energy efficiency is achieved by using the stray field of a micromagnet on a piezoelectrically actuated MEMS cantilever to locally induce this shift. The device shows a phase shift of more than 360{\deg} at a center frequency of 6.1 GHz using a phase-shifting area of less than 0.02mm$^2$. By changing the magnetic bias field, its functionality is experimentally confirmed over a range of center frequencies from 3 GHz to 8.2 GHz, and simulations show its applicability up to 14 GHz. A system-level characterization of an embedded device version demonstrates the qualification of magnonic phase shifters for highly integrated RF systems.

physics.app-ph↗

arXiv2026

In-situ Straining of Epitaxial Freestanding Ferroic Films by a MEMS Device

Mechanical strain can be used to control physical properties in materials. The experimental investigation of strain-induced effects at the nanoscale is of importance not only for its fundamental aspects, but also for the development of device applications. Transmission X-ray microscopy is a particularly well-suited technique for nanoscale imaging of magnetic materials, but its compatibility with in-situ mechanical straining of samples is limited. In this work, we present a setup for applying tailored in-situ mechanical strains to freestanding thin films by means of a micro electromechanical system (MEMS) actuator. We then present a proof-of-concept experiment in which a freestanding 80 nm thick (001) BiFeO3 multiferroic thin film is strained with the MEMS device, allowing us to control the coupled ferroelectric/spin cycloidal configuration.

cond-mat.mes-hall↗

arXiv2025

Self Biased Integrated Magnonic Device

In the race towards "beyond 6G" telecommunication platforms, magnonics emerges as a promising solution due to its wide tunability within the FR3 band (7-24 GHz). So far, however, the need for an external magnetic bias field to allow the coherent excitation of spin waves has been a major bottleneck. Conventional bulky electromagnets are power-intensive and challenging to integrate on-chip, restricting magnonic applications largely to academic research. Here, we present the first demonstration of a standalone, tunable magnonic device featuring all-electric input and output, fully integrated on a silicon substrate with a compact footprint of 100 x 150 $\mu$m. The device consists of a CoFeB waveguide equipped with two radio frequency antennas, flanked by a symmetric configuration of T-shaped magnetic flux concentrators and rectangular SmCo permanent micromagnets. By varying the distance D between the flux concentrators and the permanent magnets from 0 to 12 $\mu$m, the transverse bias field can be tuned from 20.5 mT to 11 mT, respectively. This variation directly modulates the dispersion relation of Damon-Eshbach spin wave modes in the CoFeB waveguide. In these proof-of-concept devices, the spin wave frequency band ranges from 3 to 8 GHz, with precise phase shift tuning of up to 120 degrees at 6 GHz achieved by varying D within the 0-8 $\mu$m range. The operational frequency band could even be pushed to higher frequencies through optimized micromagnet engineering.

physics.app-ph↗

arXiv2024

Three-dimensional nanoscale control of magnetism in crystalline Yttrium Iron Garnet

The exceptional magnetic, optical and phononic properties of Yttrium Iron Garnet (YIG) make it unique for spin-wave based and photonic applications. Yet, nanostructuring crystalline YIG and manipulating its magnetism in a non-destructive way is an outstanding challenge, and so far mostly limited to two-dimensional capabilities. Here, we show that irradiation of single-crystal YIG films with a focused UV laser drives a stable, giant enhancement of the perpendicular magnetic anisotropy, preserving the crystalline quality. This modulation is highly confined at the nanoscale in both the lateral and vertical directions, and its extension within the volume can be finely tuned with a continuous depth-control. By harnessing these three-dimensional anisotropy profiles, we demonstrate a large tuning of the spin-wave band structure, volume spatial localization, and non-reciprocity, realizing proof-of-principle 3D magnonic crystals. This straightforward, single-step, laser nanofabrication of three-dimensional magnetic systems based on crystalline YIG thin films opens the way to design novel functions in magnonic and magneto-optic devices.

cond-mat.mtrl-sci↗

arXiv2024

Tuning magnonic devices with on-chip permanent micromagnets

One of the most appealing features of magnonics is the easy tunability of spin-waves propagation via external magnetic fields. Usually this requires bulky and power-hungry electromagnets which are not compatible with device miniaturization. Here we propose a different approach, exploiting the stray field from permanent micromagnets integrated on the same chip of a magnonic wave-guide. In our monolithic device, we employ two SmCo square micromagnets (10x10 $\mu$m$^2$) flanking a CoFeB conduit at different distances from its axis, to produce a tunable transverse bias field between 7.5 and 3.0 mT in the conduit region between the magnets. Spin waves excited by an antenna just outside the region between the magnets enter a region with a variable higher (lower) effective field when an external bias field is applied parallel (antiparallel) to that from the micromagnets. Consequently, the attenuation length and phase shift of Damon-Eshbach spin waves can be tuned in a wide range by playing with the parallel-antiparallel configuration of the external bias and the distance between SmCo micromagnets and the CoFeB conduit. This work demonstrates the potential of permanent micro-magnets for the realization of low-power, integrated magnonic devices with tunable functionalities.

physics.app-ph↗