A5009529661- Magnetic properties of thin films
- Magneto-Optical Properties and Applications
- Advanced Memory and Neural Computing
- Neural Networks and Reservoir Computing
- Characterization and Applications of Magnetic Nanoparticles
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Acoustic Wave Resonator Technologies
- Mechanical and Optical Resonators
- Magnetic Properties and Applications
- Nonlinear Dynamics and Pattern Formation
- Molecular Junctions and Nanostructures
- Theoretical and Computational Physics
- Ferroelectric and Negative Capacitance Devices
- Magnetic and transport properties of perovskites and related materials
- Advanced MEMS and NEMS Technologies
- ZnO doping and properties
- 3D Printing in Biomedical Research
- Random lasers and scattering media
- Advanced Surface Polishing Techniques
- Optical Network Technologies
- Magnetic Properties of Alloys
- Microfluidic and Bio-sensing Technologies
- Semiconductor Quantum Structures and Devices
- Force Microscopy Techniques and Applications
University of Koblenz and Landau
2023-2025
Université Paris-Saclay
2015-2025
Centre de Nanosciences et de Nanotechnologies
2025
Centre National de la Recherche Scientifique
2012-2025
University of Kaiserslautern
2020-2025
Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
2023-2024
Lebanese University
2019-2024
Institut Jean Lamour
2017-2018
Université de Lorraine
2017-2018
Laboratoire Albert Fert
2017
It is demonstrated that the threshold current for damping compensation can be reached in a 5 μm diameter YIG(20 nm)|Pt(7 nm) disk. The demonstration rests upon measurement of ferromagnetic resonance linewidth as function I(dc) using magnetic force microscope (MRFM). shown losses spin-wave modes existing insulator reduced or enhanced by at least factor depending on polarity and intensity an in-plane dc flowing through adjacent normal metal with strong spin-orbit interaction. Complete...
Abstract Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt frequency external stimuli. This makes them interesting model systems study the effects of synchronization and brings some opportunities improve microwave characteristics in view applications information communication technologies and/or design innovative computing architectures. So far, mutual through propagating spinwaves exchange coupling a common magnetic layer has been demonstrated. Here we show...
Abstract The field of magnonics, which aims at using spin waves as carriers in data-processing devices, has attracted increasing interest recent years. We present and study micromagnetically a nonlinear nanoscale magnonic ring resonator device for enabling implementations logic gates neuromorphic circuits. In the linear regime, this efficiently suppresses spin-wave transmission phenomenon critical resonant coupling, thus exhibiting behavior notch filter. By input power, resonance frequency...
Spiking neural networks aim to emulate the brain's properties achieve similar parallelism and high processing power. A caveat of these is computational cost for emulation, while current proposals analogue implementations are energy inefficient not scalable. We propose a device based on single magnetic tunnel junction perform neuron firing spiking without need any resetting procedure. leverage two areas physics, magnetism thermal effects, obtain biorealistic behavior analogous Hodgkin-Huxley...
We investigate the microwave characteristics of a spin transfer nano-oscillator (STNO) based on coupled vortices as function perpendicular magnetic field ${H}_{\ensuremath{\perp}}$. Interestingly, we find that our vortex-based oscillator is quasi-isochronous independently ${H}_{\ensuremath{\perp}}$ and for dc current ranging between 18 25 mA. It means severe nonlinear broadening usually observed in STNOs can be suppressed broad range bias. Still, generation linewidth displays strong...
Nonlinear phenomena are crucial for magnon-based information processing, but the nonlinear interaction between two spin-wave signals requires their spatiotemporal overlap, which can be challenging directional processing devices. Our study focuses on a gallium-substituted yttrium iron garnet film, exhibits an exchange-dominated dispersion relation and, thus, provides particularly broad range of group velocities compared to pure YIG. Using time- and space-resolved Brillouin light scattering...
We study the synchronization of auto-oscillation signal generated by spin transfer driven dynamics two coupled vortices in a spin-valve nanopillar to an external source. Phase-locking microwave field hrf occurs range larger than 10% oscillator frequency for drive amplitudes only few Oersteds. Using at double frequency, generation linewidth is found decrease more five orders magnitude phase-locked regime (down 1 Hz, limited resolution bandwidth spectrum analyzer) comparison free running (140...
Finding new energy-efficient methods for exciting magnetization dynamics is one of the key challenges in magnonics. In this work, we present an approach to excite gyrotropic magnetic vortices through phenomenon inverse magnetostriction, also known as Villari effect. We develop analytical model based on Thiele formalism that describes motion vortex core including energy contributions due magnetostriction. Based model, predict excitations resonances by surface acoustic waves whose frequency...
In the race towards "beyond 6G" telecommunication platforms, magnonics emerges as a promising solution due to its wide tunability within FR3 band (7-24 GHz). So far, however, need for an external magnetic bias field allow coherent excitation of spin waves has been major bottleneck. Conventional bulky electromagnets are power-intensive and challenging integrate on-chip, restricting magnonic applications largely academic research. Here, we present first demonstration standalone, tunable device...
Magnetic vortices are highly tunable, nonlinear systems with ideal properties for being applied in spin wave emission, data storage, and neuromorphic computing. However, their technological application is impaired by a limited understanding of non-conservative forces, that results the open challenge attaining precise control over vortex dynamics coupled systems. Here, we present an analytical model gyrotropic magnetic within nano-pillar structures, revealing how conservative forces dictate...
Using a magnetic-resonance force microscope (MRFM), the power emitted by spin-transfer nano-oscillator consisting of normally magnetized Py$|$Cu$|$Py circular nanopillar is measured both in autonomous and forced regimes. From behavior subcritical region dynamics, one obtains quantitative measurement threshold current noise level. Their field dependence directly yields spin torque efficiency acting on thin layer nature mode which first auto-oscillates: lowest energy, spatially most uniform...
Spintronic technology promises to significantly increase the efficiency and scalability of neural networks by employing optimized task-oriented device components that exhibit intrinsic nonlinearity, temporal nonlocality, scalability, electrical tunability. In particular, functional response spin-transfer torque oscillators can be designed naturally emulate building blocks networks, such as short-term memory, hierarchy, nonlinearity. We propose nano-oscillators a dynamic neuron used in...
Current-induced self-sustained magnetization oscillations in spin-torque nano-oscillators (STNOs) are promising candidates for ultra-agile microwave sources or detectors. While usually STNOs behave as a monochrome source, we report here clear bimodal simultaneous emission of incommensurate oscillations, where the two tones correspond to parametrically coupled eigenmodes with tunable splitting. The range is crucially sensitive change hybridization free and fixed layers, instance, through...
Abstract The parametric excitation of spin waves by coherent surface acoustic in metallic magnetic thin film structures is demonstrated experimentally using Brillouin light scattering spectroscopy. Complementary micromagnetic simulations and analytical modeling reveal that, depending on the experimental conditions, spin‐wave instabilities originate from different phonon‐magnon magnon‐magnon processes. This opens novel ways to create micro‐scaled nonlinear magnonic systems for logic data...
Materials science and device studies have, when implemented jointly as “operando” studies, better revealed the causal link between properties of device's materials its operation, with applications ranging from gas sensing to information energy technologies. Here, a further step that maximizes this link, paper focuses on electronic those atoms drive operation by using it read out property. It is demonstrated how method can reveal insight into macroscale, industrial‐grade microelectronic...
Spin‐polarized charge transfer at the interface between a ferromagnetic (FM) metal and molecule can lead to coupling high spin polarization room temperature. The magnetic properties of these interfaces not only alter those ferromagnet but also stabilize molecular chains with interesting opportunities toward quantum computing. With aim enhance an organic spintronic device's functionality, external control over this may thus be achieved by altering ferromagnet/molecule interface's properties....
We perform a comparative study of spin transfer induced excitation the gyrotropic motion vortex core with either uniform or polarizers. The microwave output voltage associated dynamics, detected in both cases, displays strong reduction phase fluctuations case polarizer, decrease peak linewidth by one order magnitude down to 200kHz at zero field. A thorough rf emission features for different accessible configurations shows that this improvement is related coupled dynamics torques.
We propose a hybrid magnonic-oscillator system based on the combination of spin transfer auto-oscillator and magnonic waveguide to open new perspectives for spin-wave circuits. The is composed oscillator vortex state which dipolarly coupled nanoscale with longitudinal magnetization. In its auto-oscillating regime, emits coherent waves tunable controllable frequencies, directions, amplitudes into waveguide. demonstrate principle this method using micromagnetic simulations show that...
Two synthetic antiferromagnet bilayer systems with strong perpendicular anisotropy CoFeB/Ta/CoFeB and Pt/Co/Ir/Co/Pt have been grown using sputtering techniques. For both two types of magnetization transitions studied. The first one concerns from a state where magnetizations the magnetic layers are parallel (P state) to aligned antiparallel (AP state). second between possible alignments (AP+ AP-). after-effect measurements can be understood in frame nucleation-propagation model. Time...
We report on magnetic domain wall velocity measurements in a synthetic ferrimagnet made of two perpendicular ferromagnetic layers antiferromagnetically exchange coupled. In this system, types transitions may be observed: one from parallel alignment to an antiparallel the magnetization and other between possible alignments. Those are shown dominated by propagation. The as function applied field pulse amplitude has been measured. Two remarkable features first, drastic breakdown then inversion...