6 research outputs found
Manipulation of 2D and 3D Magnetic Solitons Under the Influence of DMI Gradients
No full textMagnetic solitons hold great promise for token-based computing applications due to their intrinsic properties, including small size, topological stability, ultra-low power manipulation, and potentially ultra-fast operation. In particular, they have been proposed as reliable memory units that enable the execution of various logic tasks with in-situ memory. A critical challenge remains the identification of optimal soliton and efficient manipulation techniques. Previous research has primarily focused on the manipulation of two-dimensional solitons, such as skyrmions, domain walls, and vortices, by applied currents. The discovery of novel methods to control magnetic parameters, such as the interfacial Dzyaloshinskii-Moriya interaction, through strain, temperature gradients, and applied voltages offers new avenues for energetically efficient manipulation of magnetic structures. In this work, we present a comprehensive study using numerical and analytical methods to investigate the stability and motion of various magnetic textures under the influence of DMI gradients. Our results show that Néel and Bloch-type skyrmions, as well as radial vortices, exhibit motion characterized by finite skyrmion Hall angles, while circular vortices undergo expulsion dynamics. This study provides a deeper and crucial understanding of the stability and gradient-driven dynamics of magnetic solitons, paving the way for the design of scalable spintronics token-based computing devices
Spintronic Hodgkin-Huxley-Analogue Neuron Implemented with a Single Magnetic Tunnel Junction
No full textSpiking neural networks aim to emulate the brain's properties to achieve similar parallelism and high processing power. A caveat of these neural networks is the high computational cost for emulation, while current proposals for analogue implementations are energy inefficient and not scalable. We propose a device based on a single magnetic tunnel junction to perform neuron firing for spiking neural networks without the need for any resetting procedure. We leverage two areas of physics, magnetism and thermal effects, to obtain biorealistic spiking behavior analogous to the Hodgkin-Huxley model of the neuron. The device is also able to emulate the simpler leaky-integrate-and-fire model. Numerical simulations using experimental-based parameters demonstrate firing frequency in the megahertz to gigahertz range under constant input at room temperature. The compactness, scalability, low cost, CMOS compatibility, and power efficiency of magnetic tunnel junctions advocates for their broad use in hardware implementations of spiking neural networks
A spintronic Huxley-Hodgkin-analogue neuron implemented with a single magnetic tunnel junction
No full textSpiking neural networks aim to emulate the brain's properties to achieve
similar parallelism and high-processing power. A caveat of these neural
networks is the high computational cost to emulate, while current proposals for
analogue implementations are energy inefficient and not scalable. We propose a
device based on a single magnetic tunnel junction to perform neuron firing for
spiking neural networks without the need of any resetting procedure. We
leverage two physics, magnetism and thermal effects, to obtain a bio-realistic
spiking behavior analogous to the Huxley-Hodgkin model of the neuron. The
device is also able to emulate the simpler Leaky-Integrate and Fire model.
Numerical simulations using experimental-based parameters demonstrate firing
frequency in the MHz to GHz range under constant input at room temperature. The
compactness, scalability, low cost, CMOS-compatibility, and power efficiency of
magnetic tunnel junctions advocate for their broad use in hardware
implementations of spiking neural networks.Comment: 23 pages, 6 figures, 2 table
Manipulation of magnetic solitons under the influence of DMI gradients
No full textMagnetic solitons are promising for applications due to their intrinsic
properties such as small size, topological stability, ultralow power
manipulation and potentially ultrafast operations. To date, research has
focused on the manipulation of skyrmions, domain walls, and vortices by applied
currents. The discovery of new methods to control magnetic parameters, such as
the interfacial Dzyaloshinskii-Moriya interaction (DMI) by strain, geometry
design, temperature gradients, and applied voltages promises new avenues for
energetically efficient manipulation of magnetic structures. The latter has
shown significant progress in 2d material-based technology. In this work, we
present a comprehensive study using numerical and analytical methods of the
stability and motion of different magnetic textures under the influence of DMI
gradients. Our results show that under the influence of linear DMI gradients,
N\'eel and Bloch-type skyrmions and radial vortex exhibit motion with finite
skyrmion Hall angle, while the circular vortex undergoes expulsion dynamics.
This work provides a deeper and crucial understanding of the stability and
gradient-driven dynamics of magnetic solitons, and paves the way for the design
of alternative low-power sources of magnetization manipulation in the emerging
field of 2d materials.Comment: 19 pages, 5 figure
Simultaneous multitone microwave emission by dc-driven spintronic nano-element
No full textInternational audienceCurrent-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 monochromatic source, we report here clear bimodal simultaneous emission of incommensurate microwave oscillations in the frequency range of 6 to 10 gigahertz at femtowatt level power. These two tones correspond to two parametrically coupled eigenmodes with tunable splitting. The emission range is crucially sensitive to the change in hybridization of the eigenmodes of free and fixed layers, for instance, through a slight tilt of the applied magnetic field from the normal of the nanopillar. Our experimental findings are supported both analytically and by micromagnetic simulations, which ascribe the process to four-magnon scattering between a pair of radially symmetric magnon modes and a pair of magnon modes with opposite azimuthal index. Our findings pave the way for enhanced cognitive telecommunications and neuromorphic systems that use frequency multiplexing to improve communication performance
Simultaneous multitone microwave emission by dc-driven spintronic nano-element
No full textCurrent-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 monochromatic source, we report here clear bimodal simultaneous emission of incommensurate microwave oscillations in the frequency range of 6 to 10 gigahertz at femtowatt level power. These two tones correspond to two parametrically coupled eigenmodes with tunable splitting. The emission range is crucially sensitive to the change in hybridization of the eigenmodes of free and fixed layers, for instance, through a slight tilt of the applied magnetic field from the normal of the nanopillar. Our experimental findings are supported both analytically and by micromagnetic simulations, which ascribe the process to four-magnon scattering between a pair of radially symmetric magnon modes and a pair of magnon modes with opposite azimuthal index. Our findings pave the way for enhanced cognitive telecommunications and neuromorphic systems that use frequency multiplexing to improve communication performance
