arXiv subjects

Ádám Papp

Publications and source records attributed to Ádám Papp.

7 recordsLinked to original sources

arXiv2026

Establishing the Magnetoelastic Origin of Spin-Wave Routing through Focused Ion Beam Patterning

Spin waves are promising information carriers for analog and wave-based computing, where functionality relies on compact and precisely engineered scattering landscapes. Focused ion beam (FIB) irradiation enables such control by locally tailoring the spin-wave dispersion in yttrium iron garnet (YIG). However, a non-monotonic dependence of the spin-wave wavelength on increasing ion dose hinders predictive landscape design. Here, we present an experimentally validated framework that explains this non-monotonic spin-wave steering by linking phenomenological strain-induced anisotropy to its magnetoelastic origin. Irradiation-induced lattice dislocations drive elastic and plastic deformation, which evolve into partial amorphization, each stage contributing distinctly to the dispersion behavior. We combine post-irradiation wet-chemical etching and atomic force microscopy (AFM) to quantify thickness changes, and track the dispersion in etched regions using time-resolved magneto-optical Kerr effect (trMOKE) microscopy. Fitting the data to the Kalinikos--Slavin formalism with an added effective magnetoelastic field isolates contributions from elastic and plastic deformation. Validation is achieved by mapping the deformation evolution onto a three-phase scenario based on SRIM simulations, reproducing the extracted field trends, and by consistent strain tensor and micromagnetic analyses. These results establish a physical basis for FIB-engineered graded-index (GRIN) spin-wave landscapes and magnetoelastically programmable magnonic devices.

physics.app-ph↗

arXiv2026

Design and Realization of Broadband Magnonic Spectrometers With Local Electrical Outputs

Microscopic radio-frequency (RF) devices based on propagating spin waves (SWs) are promising for compact, energy-efficient RF signal processing, but their implementation is impeded by fabrication complexity and the lack of efficient electrical readout. In this work, we demonstrate a SW-based Rowland circle spectrometer with electrical input and local electrical output transducers. The device is realized using a scalable fabrication process based on sputter deposition and wet-chemical etching of Yttrium-Iron-Garnet (YIG), forming concave grating structures with micrometer-scale features. The device functionality is confirmed by combined electrical and magneto-optical measurements, which show that the deflection of SW wavefronts at different input frequencies closely follows the analytically predicted behavior. The linear excitation of SWs via two input tones further confirms the spectrometer operation for simultaneously propagating waves. Beyond the single-device demonstration, we propose a concept for scalable architectures comprising multiple Rowland circles with tunable operating points. When combined with broadband parallel electrical readout, this approach enables control over bandwidth and spectral resolution, which are relevant to spectral occupancy detection in wireless communication systems.

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° 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

Reprogrammable magnonic logic in a multiferroic heterostructure via magnetoelectric coupling

The realization of fully reconfigurable, voltage-controlled, and programmable on-chip magnonic devices is essential to fully harness the potential of spin waves for signal processing, logic and neuromorphic computing. Yet, existing demonstrations of electrical tuning of magnonic responses are either volatile, current-driven and thus energy-inefficient, or rely on local strain modification limiting their scalability for wafer-scale integration. Here, we address this challenge using a BiFeO3/La0.67Sr0.33MnO3 multiferroic thin film heterostructure. We show that ferroelectric domain engineering in BiFeO3 enables deterministic tuning of the magnon dispersion of La0.67Sr0.33MnO3, producing frequency shifts up to $\sim 150 MHz$ and allowing reconfigurable waveguiding. Micro-focused Brillouin light scattering directly images these effects, revealing electrically defined magnonic waveguides and spatially programmable dispersion. Compared to conventional approaches, this method provides non-volatile and reversible control. Furthermore, using an inverse-design simulation code, we demonstrate the capability of our platform to perform advanced magnonic functions such as frequency demultiplexing. Our results open a new avenue for using magnetoelectric heterostructures for magnonic logic, with further applicability to reservoir and neuromorphic computing and AI driven magnonic devices.

cond-mat.mes-hall↗

arXiv2025

Identification and minimization of losses in microscaled spin-wave transducers

Magnonics is a promising platform for integrated radio frequency (rf) devices, leveraging its inherent non-reciprocity and reconfigurability. However, the efficiency of spin-wave transducers driven by rf-currents remains a major challenge. In this study, we systematically investigate a spin-wave transducer composed of micron-sized rf antennas on yttrium iron garnet (YIG) films of different thickness - an ideal testbed for integrated magnonic devices. Using propagating spin-wave spectroscopy and numerical simulations, we analyze spin-wave transmission, identifying key loss mechanisms and improving device efficiency by reducing ohmic resistance. The resulting improvements enable the reduction of insertion loss to below $\SI{10}{dB}$ in microscaled spin-wave transducers. At the same time large non-reciprocity can be exploited to achieve significant isolation on the microscale.

physics.app-ph↗

arXiv2024

Design rules for low-insertion-loss magnonic transducers

We present a computational framework for the design of magnonic transducers, where waveguide antennas generate and pick up spin-wave signals. Our method relies on the combination of circuit-level models with micromagnetic simulations and allows simulation of complex geometries in the magnonic domain. We validated our model with experimental measurements, which showed good agreement witch the predicted scattering parameters of the system. Using our model we identified scaling rules of the antenna radiation resistance and we show strategies to maximize transduction efficiency between the electric and magnetic domains. We designed a transducer pair on YIG with 5dB insertion loss in a 100 MHz band, an unusually low value for micron-scale spin-wave devices. This demonstrates that magnonic devices can be very efficient and competitive in RF applications.

physics.app-ph↗

arXiv2023

Secondary Excitation of Spin-Waves: How Electromagnetic Cross-Talk Impacts on Magnonic Devices

This work examines the impact of electromagnetic cross-talk in magnonic devices when using inductive spin-wave (SW) transducers. We present detailed electrical SW spectroscopy measurements showing the signal contributions to be considered in magnonic device design. We further provide a rule of thumb estimation for the cross-talk that is responsible for the secondary SW excitation at the output transducer. Simulations and calibrated electrical characterizations underpin this method. Additionally, we visualize the secondary SW excitation via time-resolved MOKE imaging in the forward-volume configuration in a 100nm Yttrium-Iron-Garnet (YIG) system. Our work is a step towards fast yet robust joint electromagentic-micromagnetic magnonic device design.

physics.app-ph↗