arXiv subjects

Levente Maucha

Publications and source records attributed to Levente Maucha.

3 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↗

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↗

arXiv2022

Experimental Demonstration of a Spin-Wave Lens Designed with Machine Learning

We present the design and experimental realization of a device that acts like a spin-wave lens i.e., it focuses spin waves to a specified location. The structure of the lens does not resemble any conventional lens design, it is a nonintuitive pattern produced by a machine learning algorithm. As a spin-wave design tool, we used our custom micromagnetic solver "SpinTorch" that has built-in automatic gradient calculation and can perform backpropagation through time for spin-wave propagation. The training itself is performed with the saturation magnetization of a YIG film as a variable parameter, with the goal to guide spin waves to a predefined location. We verified the operation of the device in the widely used mumax3 micromagnetic solver, and by experimental realization. For the experimental implementation, we developed a technique to create effective saturation-magnetization landscapes in YIG by direct focused-ion-beam irradiation. This allows us to rapidly transfer the nanoscale design patterns to the YIG medium, without patterning the material by etching. We measured the effective saturation magnetization corresponding to the FIB dose levels in advance and used this mapping to translate the designed scatterer to the required dose levels. Our demonstration serves as a proof of concept for a workflow that can be used to realize more sophisticated spin-wave devices with complex functionality, e.g., spin-wave signal processors, or neuromorphic devices.

physics.app-ph↗