We have used the properties of topologically protected magnetic particle-like structures called skyrmions to perform a fundamental operation of neuromorphic computing: the weighted summation of synaptic signals. These skyrmions, which act as analogs of neurotransmitters in a biological neural network, enabled the reproduction of this operation in a compact and energy-efficient manner, opening up new possibilities for neuromorphic components that approach the efficiency of biological systems. The recently published article is here: Nature Electronics 2025 [arXiv]

Figure: Weighted summation in a device composed of two parallel tracks (synapses) made of a magnetic multilayer.
(a-d) Kerr microscopy images of the device, which consists of two parallel magnetic multilayer tracks, each 6 µm wide, connected by a transverse Ta Hall electrode, also 6 µm wide. After magnetization saturation of the track (a), skyrmions can be selectively nucleated in track 1 (b) and track 2 (c), before being erased by an inverse field or current (d).
(e) Hall voltage ∆V (in red) and the corresponding sum of the detected skyrmion count in both tracks, ∑NSk, detec (in blue), during the successive injection of skyrmions into the tracks. 20 nucleation pulses are sequentially applied to each track (indicated by the green and yellow regions for tracks 1 and 2, respectively) using current pulses of approximately 116 GA/m² and 50 ns, at µ0Hz = 20 mT. The thin red curve represents the raw electrical measurements after drift correction, while the thick curve is the same after smoothing.