A5063417411- Magnetic properties of thin films
- Quantum and electron transport phenomena
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Physics of Superconductivity and Magnetism
- Advanced Memory and Neural Computing
- Magnetic Properties of Alloys
- Ferroelectric and Negative Capacitance Devices
- Multiferroics and related materials
- Magneto-Optical Properties and Applications
- Mechanical and Optical Resonators
- Magnetic and transport properties of perovskites and related materials
- Characterization and Applications of Magnetic Nanoparticles
- Energy Harvesting in Wireless Networks
- Nonlinear Dynamics and Pattern Formation
- Metallic Glasses and Amorphous Alloys
- Carbon Nanotubes in Composites
- Force Microscopy Techniques and Applications
- Synthesis and Characterization of Heterocyclic Compounds
- Acoustic Wave Resonator Technologies
- Synthesis and biological activity
- Surface and Thin Film Phenomena
- Synthesis of heterocyclic compounds
- Metamaterials and Metasurfaces Applications
- Neural Networks and Reservoir Computing
University of Messina
2016-2025
Istituto Nazionale di Geofisica e Vulcanologia
2021
Understanding the physical properties of magnetic skyrmions is important for fundamental research with aim to develop new spintronic device paradigms where both logic and memory can be integrated at same level. Here, we show a universal model based on micromagnetic formalism that used study skyrmion stability as function field temperature. We consider ultrathin, circular ferromagnetic dots. Our results small radius---compared dot radius---are always metastable, while large radius form stable...
Solitons are very promising for the design of next generation ultralow power devices storage and computation. The key ingredient to achieving this goal is fundamental understanding their stabilization manipulation. Here, we show how interfacial Dzyaloshinskii-Moriya Interaction (IDMI) able lift energy degeneracy a magnetic vortex state by stabilizing topological soliton with radial chirality, hereafter called vortex. It has noninteger Skyrmion number $S$ ($0.5<|S|<1$) due both core polarity...
A broadband spintronic diode would be important for electromagnetic energy harvesting, with the advantages of nanoscale size and low output resistance. This study gives experimental proof microwave detection in a magnetic tunnel junction, providing sufficient dc voltage to supply low-power nanodevice. Such diodes also work as rectifiers below 1 nW, outperforming traditional Schottky diodes. These results point building blocks self-powered systems such implantable biomedical devices, wireless...
Magnetic skyrmions are topologically protected states that very promising for the design of next generation ultralow-power electronic devices. In this letter, we propose a magnetic tunnel junction based spin-transfer torque diode with skyrmion as ground state and perpendicular polarizer patterned nanocontact local injection current. The key result is possibility to achieve sensitivities (i.e. detection voltage over input microwave power) larger than 2000V/W optimized contact diameters. Our...
This paper shows how to implement a semi-implicit algorithm based on the Adams-Bashforth as predictor, and second order Adams-Moulton procedure corrector in Landau–Lifshitz–Gilbert-Slonczewski equation. We compare results with Runge-Kutta scheme of 5th order, while for standard problem #4 (and, general, LLG equation) computational speeds are same we found better performance when thermal fluctuations or spin-polarized currents taken into account.
This letter studies the dynamical behavior of spin-Hall nanoscillators from a micromagnetic point view. The model parameters have been identified by reproducing recent experimental data quantitatively. Our results indicate that strongly localized mode is observed for in-plane bias fields such as in experiments, while predict excitation an asymmetric propagating large enough out-of plane field similarly to what spin-torque nanocontact oscillators. findings show can find application spin-wave...
Abstract Materials hosting magnetic skyrmions at room temperature could enable compact and energetically-efficient storage such as racetrack memories, where information is coded by the presence/absence of forming a moving chain through device. The skyrmion Hall effect leading to their annihilation edges can be suppressed, for example, antiferromagnetically-coupled skyrmions. However, avoiding modifications inter-skyrmion distances remains challenging. As solution, bits also encoded two...
Spintronic diodes are emerging as disruptive candidates for impacting several technological applications ranging from the Internet of Things to Artificial Intelligence. In this letter, an overview recent achievements on spintronic is briefly presented, underling major breakthroughs that have led these devices largest sensitivity measured up date a diode. For each class (passive, active, resonant, non-resonant), we indicate remaining developments improve performances well future directions....
The static and dynamic properties of skyrmions have recently received increased attention due to the potential application as information carriers for unconventional computing. While current-driven dynamics has been explored deeply, both theoretically experimentally, theory temperature gradient-induced dynamics---skyrmion caloritronics---is still at its early stages development. Here, we move topic forward by identifying role entropic torques dependence magnetic parameters. Our results show...
Abstract Spin-Hall oscillators (SHO) are promising sources of spin-wave signals for magnonics applications, and can serve as building blocks magnonic logic in ultralow power computation devices. Thin magnetic layers used “free” SHO contact with heavy metals having large spin-orbital interaction, and, therefore, could be subject to the spin-Hall effect (SHE) interfacial Dzyaloshinskii-Moriya interaction ( i -DMI), which may lead nonreciprocity excited spin waves other unusual effects. Here,...
Abstract Spintronics-based microwave devices, such as oscillators and detectors, have been the subject of intensive investigation in recent years owing to potential reductions size power consumption. However, only a few concepts for spintronic amplifiers proposed, typically requiring complex device configurations or material stacks. Here, we demonstrate amplifier based on two-terminal magnetic tunnel junctions (MTJs) produced with CMOS-compatible stacks that already used spin-transfer torque...
Abstract Current-driven magnetic skyrmions show promise as carriers of information bits in racetrack memory applications. Specifically, the utilization synthetic antiferromagnetic (SAF) systems is highly attractive due to potential suppress Skyrmion Hall effect, which causes a transverse displacement driven relative shift direction. In this study, we demonstrate, through analytical calculations and micromagnetic simulations, that case nanoring geometry, current-driven achieve stable circular...
The realistic modeling of spin-transfer torque (STT)-magnetoresistive random access memory (MRAM) for the simulations hybrid CMOS/Spintronics devices in comprehensive simulation environments requires a full description stochastic switching processes state-of-the-art STT-MRAMs. Here, we compare micromagnetic with an analytical formulation that takes into account spin-torque asymmetry spin-polarization function by considering mean, standard deviation, skewness, and kurtosis. We find that,...
The understanding of the dynamical properties skyrmion is a fundamental aspect for realization competitive based technology beyond CMOS. Most theoretical approaches are on approximation rigid skyrmion. However, thermal fluctuations can drive continuous change size via excitation modes. Here, by taking advantage Hilbert-Huang transform, we demonstrate that at least two modes be excited which non-stationary in time. In addition, one limit this hypothesis does not allow correctly describing...
The nonautonomous dynamics of spin-torque oscillators in the presence both microwave current and field at same frequency can exhibit complex nonisochronous effects. A nonstationary mode hopping between quasiperiodic (frequency pulling) periodic (phase locking) a deterministic phase slip characterized by an oscillatory synchronization transient (non-Adlerian slip) after jump $\ifmmode\pm\else\textpm\fi{}2\ensuremath{\pi}$ were predicted. In latter effect, wavelet-based analysis reveals that...
This paper micromagnetically studies the magnetization dynamics driven by spin-Hall effect in a Platinum/Permalloy bi-layer. For certain field and current range, excitation of uniform mode, characterized power with spatial distribution whole ferromagnetic cross section, is observed. We suggest to use ferromagnet bi-layer as basis for realization an array spin-torque oscillators (STOs): Permalloy will act shared free layer, whereas spacers polarizers are built on top it. Following this...
A strategy for a scalable synchronization of an array spin-Hall oscillators (SHOs) is illustrated. In detail, we present the micromagnetic simulations two and five SHOs realized by means couples triangular golden contacts on top Pt/CoFeB/Ta trilayer. The results highlight that occurs whole current region gives rise to excitation self-oscillations. This linked role magnetodipolar coupling, which phenomenon driving when distance between not too large. Synchronization also turns out be robust...
Spintronic diodes (STDs) are emerging as a technology for the realization of high-performance microwave detectors. The key advantages such devices their high sensitivity, capability to work at low input power, and compactness. In this work, we show possible use STDs neuromorphic computing expanding realm functionalities implement analog multiplication, which is operation in convolutional neural networks (CNN). particular, introduce concept degree rectification (DOR) injection-locked STDs....
Spintronic technology is emerging as a direction for the hardware implementation of neurons and synapses neuromorphic architectures. In particular, single spintronic device can be used to implement nonlinear activation function neurons. Here, we propose how with sigmoidal ReLU-like functions. We then perform numerical experiment showing robustness neural networks made by all having different functions emulate device-to-device variations in possible network. Therefore, consider vanilla...