In this work , we describe the design, realisation and characterization of the magnetic version of the Galton Board, an archetypal statistical device originally designed to exemplify normal distributions. Although simple in its macroscopic form, achieving an equivalent nanoscale system poses many challenges related to the generation of sufficiently similar nanometric particles and the strong influence that nanoscale defects can have in the stochasticity of random processes. We demonstrate how the quasi-particle nature and the chaotic dynamics of magnetic domain-walls can be harnessed to create nanoscale stochastic devices [1]. Furthermore, we show how the direction of an externally applied magnetic field can be employed to controllably tune the probability distribution at the output of the devices, and how the removal of elements inside the array can be used to modify such distribution.
For numerous Radio-Frequency applications such as medicine, RF fingerprinting or radar classification, it is important to be able to apply Artificial Neural Network on RF signals. In this work we show that it is possible to apply directly Multiply-And-Accumulate operations on RF signals without digitalization, thanks to Magnetic Tunnel Junctions (MTJs). These devices are similar to the magnetic memories already industrialized and compatible with CMOS.
We show experimentally that a chain of these MTJs can rectify simultaneously different RF signals, and that the synaptic weight encoded by each junction can be tune with their resonance frequency.
Through simulations we train a layer of these junctions to solve a handwritten digit dataset. Finally, we show that our system can scale to multi-layer neural networks using MTJs to emulate neurons.
Our proposition is a fast and compact system that allows to receive and process RF signals in situ and at the nanoscale.
Manipulation of magnetic chirality is of outermost importance due to the great technological and scientific opportunities it unlocks. Over the last decade, this manipulation has been achieved through the harnessing of chiral spin interactions in non-centrosymmetric materials and thin film interfaces (DMI), allowing for the creation and tuning of topologically non-trivial chiral spin textures such as spin-spirals and Skyrmions, of great scientific and technological interest. Here we will discuss how state of the art 3D nano-printing can be employed to create 3D geometries that host complex chiral spin textures and how such geometries can be combined to create artificial interfaces where spin textures of different chirality are forced to match each other [1]. Characterization of the resulting spin states using magnetic X-ray microscopy will be presented.
[1] Sanz-Hernández, D., et al. arXiv:2001.07130 [cond-mat.mes-hall]
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.