8 research outputs found
Voltage control of domain walls in magnetic nanowires for energy efficient neuromorphic devices
An energy-efficient voltage controlled domain wall device for implementing an
artificial neuron and synapse is analyzed using micromagnetic modeling in the
presence of room temperature thermal noise. By controlling the domain wall
motion utilizing spin transfer or spin orbit torques in association with
voltage generated strain control of perpendicular magnetic anisotropy in the
presence of Dzyaloshinskii-Moriya interaction, different positions of the
domain wall are realized in the free layer of a magnetic tunnel junction to
program different synaptic weights. The feasibility of scaling of such devices
is assessed in the presence of thermal perturbations that compromise
controllability. Additionally, an artificial neuron can be realized by
combining this DW device with a CMOS buffer. This provides a possible pathway
to realize energy efficient voltage controlled nanomagnetic deep neural
networks that can learn in real time
Magnetic domain walls : Types, processes and applications
Domain walls (DWs) in magnetic nanowires are promising candidates for a
variety of applications including Boolean/unconventional logic, memories,
in-memory computing as well as magnetic sensors and biomagnetic
implementations. They show rich physical behaviour and are controllable using a
number of methods including magnetic fields, charge and spin currents and
spin-orbit torques. In this review, we detail types of domain walls in
ferromagnetic nanowires and describe processes of manipulating their state. We
look at the state of the art of DW applications and give our take on the their
current status, technological feasibility and challenges.Comment: 32 pages, 25 figures, review pape
Energy Efficient Spintronic Device for Neuromorphic Computation
Future computing will require significant development in new computing device paradigms. This is motivated by CMOS devices reaching their technological limits, the need for non-Von Neumann architectures as well as the energy constraints of wearable technologies and embedded processors. The first device proposal, an energy-efficient voltage-controlled domain wall device for implementing an artificial neuron and synapse is analyzed using micromagnetic modeling. By controlling the domain wall motion utilizing spin transfer or spin orbit torques in association with voltage generated strain control of perpendicular magnetic anisotropy in the presence of Dzyaloshinskii-Moriya interaction (DMI), different positions of the domain wall are realized in the free layer of a magnetic tunnel junction to program different synaptic weights. Additionally, an artificial neuron can be realized by combining this DW device with a CMOS buffer. The second neuromorphic device proposal is inspired by the brain. Membrane potential of many neurons oscillate in a subthreshold damped fashion and fire when excited by an input frequency that nearly equals their Eigen frequency. We investigate theoretical implementation of such “resonate-and-fire” neurons by utilizing the magnetization dynamics of a fixed magnetic skyrmion based free layer of a magnetic tunnel junction (MTJ). Voltage control of magnetic anisotropy or voltage generated strain results in expansion and shrinking of a skyrmion core that mimics the subthreshold oscillation. Finally, we show that such resonate and fire neurons have potential application in coupled nanomagnetic oscillator based associative memory arrays