A5047549154- Magnetic properties of thin films
- Quantum and electron transport phenomena
- Advanced Memory and Neural Computing
- Neural Networks and Reservoir Computing
- Advanced Thermoelectric Materials and Devices
- Anodic Oxide Films and Nanostructures
- Ferroelectric and Negative Capacitance Devices
- Nonlinear Dynamics and Pattern Formation
- Thermal Radiation and Cooling Technologies
- Neural Networks and Applications
- Physics of Superconductivity and Magnetism
- Characterization and Applications of Magnetic Nanoparticles
- Thermal properties of materials
- Neural dynamics and brain function
- Advanced Sensor and Energy Harvesting Materials
- Nanoporous metals and alloys
- Photonic Crystals and Applications
- Graphene research and applications
- Multiferroics and related materials
- Theoretical and Computational Physics
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Advanced Thermodynamics and Statistical Mechanics
- Ferroelectric and Piezoelectric Materials
- Electrodeposition and Electroless Coatings
UCLouvain
2014-2024
Laboratoire Albert Fert
2014-2022
Centre National de la Recherche Scientifique
2014-2022
Université Paris-Saclay
2016-2021
Université Paris-Sud
2014-2021
National Institute of Advanced Industrial Science and Technology
2019
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
2014-2016
Institut des Arts de Diffusion
2014-2016
National Institute of Engineering, Technology and Innovation
1993
Stochastic computing (SC), a radical rethinking of computation, defines operations on streams random bits; it trades precision for large advantages in speed. Implementation has been thwarted, though, by the lack an efficient means to properly decorrelate bitstreams at each logic gate SC circuit. This study harnesses recent advances manipulating magnetic skyrmions propose technique telegraph-signal reshuffling that is tailor-made applications. Leveraging two-dimensional diffusive character...
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...
Spin-torque nano-oscillators can emulate neurons at the nanoscale. Recent works show that non-linearity of their oscillation amplitude be leveraged to achieve waveform classification for an input signal encoded in voltage. Here, we frequency and phase oscillator also used recognize waveforms. For this purpose, phase-lock waveform, which carries information its modulated frequency. In way, considerably decrease amplitude, phase, noise. We method allows classifying sine square waveforms with...
The reservoir computing neural network architecture is widely used to test hardware systems for neuromorphic computing. One of the preferred tasks bench-marking such devices automatic speech recognition. This task requires acoustic transformations from sound waveforms with varying amplitudes frequency domain maps that can be seen as feature extraction techniques. Depending on conversion method, these sometimes obscure contribution overall recognition performance. Here, we quantify and...
Phase locking dynamics of dipolarly coupled vortices excited by spin-polarized current in two identical nanopillars is studied as a function the interpillar distance $L$. Numerical study and an analytical model have proved remarkable efficiency magnetostatic interaction achieving phase locking. Investigating transient regime toward locking, we extract evolution time $\ensuremath{\tau}$, coupling strength $\ensuremath{\mu}$, energy $W$. Finally, compare this with one obtained simple model.
The recent demonstration of neuromorphic computing with spin-torque nano-oscillators has opened a path to energy efficient data processing. success this hinged on the intrinsic short-term memory oscillators. In study, we extend through time-delayed feedback. We leverage extrinsic increase efficiency solving pattern recognition tasks that require discriminate different inputs. large tunability these non-linear oscillators allows us control and optimize delayed feedback using operating...
Abstract With conventional transistor technologies reaching their limits, alternative computing schemes based on novel are currently gaining considerable interest. Notably, promising approaches have proposed to leverage the complex dynamics emerging in networks of coupled oscillators nanotechnologies. The physical implementation such architectures remains a true challenge, however, as most ideas not robust nanotechnology devices’ non-idealities. In this work, we propose and investigate an...
Spin caloritronics has recently emerged from the combination of spintronics and thermoelectricity. Here, we show that flexible, macroscopic spin caloritronic devices based on large-area interconnected magnetic nanowire networks can be used to enable controlled Peltier cooling electronic components with an external field. We experimentally demonstrate three-dimensional CoNi/Cu multilayered exhibit extremely high, magnetically modulated thermoelectric power factor up 7.5 mW/K2m large...
Abstract Deep learning has an increasing impact to assist research, allowing, for example, the discovery of novel materials. Until now, however, these artificial intelligence techniques have fallen short discovering full differential equation experimental physical system. Here we show that a dynamical neural network, trained on minimal amount data, can predict behavior spintronic devices with high accuracy and extremely efficient simulation time, compared micromagnetic simulations are...
We investigate analytically and numerically the synchronization dynamics of dipolarly coupled vortex based Spin-Torque Nano Oscillators with different pillar diameters. identify critical interpillar distances on which occurs as a function their diameter mismatch. obtain phase diagram showing transition between unsynchronized synchronized states compare it to analytical predictions we make using Thiele approach. Our study demonstrates that for relatively small differences can be described...
We fabricated a perpendicularly magnetized bit pattern media using hexagonally close-packed auto-assembled anodic alumina template with 100 nm and 50 periods by depositing Co/Pt multilayer to form an ordered array of ferromagnetic nanodots, so-called nanobumps. used Hall resistance measurements magnetic force microscopy characterize the dot-by-dot magnetization reversal mechanism under applied field. The role interdot exchange coupling dipolar are investigated. Then we focus on separating...
We report on a theoretical study of the magnetodipolar coupling and synchronization between two vortex-based spin-torque nano-oscillators (STVOs). In this work we dependence efficiency relative magnetization parameters vortices in system. This is performed order to propose an optimized configuration for synchronizing STVOs. For purpose, combine micromagnetic simulations, Thiele equation approach, analytical macrodipole approximation model identify achieving phase-locking neighboring...
Fabricating powerful neuromorphic chips the size of a thumb requires miniaturizing their basic units: synapses and neurons. The challenge for neurons is to scale them down submicrometer diameters while maintaining properties that allow reliable information processing: high signal noise ratio, endurance, stability, reproducibility. In this work, we show compact spin-torque nano-oscillators can naturally implement such neurons, quantify ability realize an actual cognitive task. particular,...
Abstract Spin‐related effects in thermoelectricity can be used to design more efficient refrigerators and offer promising applications for the harvesting of thermal energy. The key challenge is structural compositional magnetic material systems with sufficiently high efficiency power output transforming energy into electric vice versa. fabrication large‐area 3D interconnected Co/Cu nanowire networks demonstrated, thereby enabling controlled Peltier cooling macroscopic electronic components...
NiFe alloy and NiFe/Cu multilayered nanowire (NW) networks were grown using a template-assisted electrochemical synthesis method. The NW exhibit large thermopower, which is largely preserved in the current perpendicular-to-plane geometry of structure. Giant magneto-thermopower (MTP) effects have been demonstrated NWs with value 25% at 300 K reaching 60% around 100 K. A spin-dependent Seebeck coefficient -12.3 μV/K was obtained room temperature. MTP demonstrate magnetic approach to control...
Electrochemical deposition of interconnected nanowires and nanotubes made ferromagnetic metals into track-etched polycarbonate templates with crossed nanochannels has been revealed suitable for the fabrication mechanically stable three-dimensional magnetic nanostructures large surface area. These 3D networks embedded flexible polymer membranes are also planar lightweight. This technique allows control geometric characteristics material composition nanowire or nanotube networks, which can be...
Thermoelectric energy conversion based on flexible materials has great potential for applications in the fields of low-power heat harvesting and solid-state cooling. Here, we show that three-dimensional networks interconnected ferromagnetic metal nanowires embedded a polymer film are effective as active Peltier coolers. Thermocouples Co-Fe exhibit much higher power factors thermal conductivities near room temperature than other existing thermoelectric systems, with factor nanowire-based...
We developed a method to fabricate ordered Co/Pt multilayer nanodot arrays using the barrier layer of anodic alumina templates as two-dimensional curved substrates. Large area patterning self-assembled nanobumps are formed with hexagonally close-packed order. The subsequent deposition multilayers on this bumpy surface leads an array single-domain nanocaps magnetized perpendicularly sample surface. Measurement reversal field function angle and images demagnetized state, composed monobump-wide...
Recently, interconnected nanowire networks have been found suitable as flexible macroscopic spin caloritronic devices. The 3D are fabricated by direct electrodeposition in track-etched polymer templates with crossed nano-channels. This technique allows the fabrication of nanowires consisting both homogeneous ferromagnetic metals and multilayer stack successive layers non-magnetic metals, controlled morphology material composition. exhibit extremely high, magnetically modulated thermoelectric...
Magnetoresistance and thermopower of crossed NiCr CoCr nanowire networks have been measured as a function temperature chromium content in dilute alloys. At low temperatures, it is found that the impurity effect leads to negative anisotropic magnetoresistance, an observation even persists until room diluted alloy nanowires. The addition small amount Cr nickel nanowires also abruptly reverses sign from −20 μV/K for pure Ni up +18 alloys, implying switching n- p-type conduction. These results...
We report on microwave oscillations induced by spin-transfer torque in metallic spin valves obtained electrodeposition of Co-Cu-Co trilayer structures nanoporous alumina templates. Using micromagnetic calculations performed similar spin-valve it was possible to identify the magnetization dynamics associated with experimentally determined emission. Furthermore appears that our particular geometry emission is generated vortex gyrotropic motion which occurs in, at least, one two magnetic layers...
A combined bottom-up assembly of electrodeposited nanowires and electron beam lithography technique has been developed to investigate the spin transfer torque microwave emission on specially designed containing a single Co/Cu/Co pseudo valve. Microwave signals have obtained even at zero magnetic field. Interestingly, high frequency vs. field tunability was demonstrated, in range 0.4–2 MHz/Oe, depending orientation applied relative layers The values emitted signal as function external are...