Fig. 5: 2D spintronic devices for in-sensor computing.

a–e Schematic of spin alignments in 2D magnetic systems: a Ferromagnetism: All spins align parallel, producing net magnetization. b Antiferromagnetism: Spins align in antiparallel sublattices, canceling net magnetization. c Altermagnetism: Antiparallel spin sublattices connected by crystallographic rotational symmetry (e.g., 2-fold, 4-fold, 6-fold), which are distinct from inversion, translation, or mirror symmetry. d Skyrmions: Topological spin textures with fixed chirality, where spins swirl continuously from “up” at the periphery to “down” at the core. e Merons: Half-skyrmion excitations where spins transition from in-plane orientations at the periphery to “down” at the core. f Schematic of a spin valve device using Fe₃GeTe₂ as the magnetic layer and h-BN as an insulating barrier. Thin Fe₃GeTe₂ layers (L1: ~7 nm, L2: ~20 nm) are separated by an atomically thin h-BN layer and encapsulated by a thicker h-BN layer. g Schematic of a Cr₂Ge₂Te₆/P(VDF-TrFE) multiferroic heterostructure, sandwiched between an ITO/Au top electrode and a SiO₂/Si substrate. h Probabilistic computing with p-bits, where bias voltage controls the probability distribution between two states. i Transfer curve of a perpendicular magnetic tunnel junction based on an AlO_x barrier, demonstrating magnetic sensing capabilities. j Voltage-dependent magnetic coercivity in a 2L-Cr₂Ge₂Te₆/P(VDF-TrFE) heterostructure at 4 K, showing coercivity modulation and memory functionality under different applied voltages. k Schematic of spin splitter torque devices, where spin polarization from altermagnetism flips the adjacent free ferromagnetic layer. l Schematic of a skyrmionic synaptic device, where bidirectional learning stimuli move skyrmions into (potentiation) or out of (depression) the postsynapse region, mimicking biological synapses. m Skyrmion-based neuromorphic computing concept, showing a Hall bar device and a magnetic skyrmion reservoir for computation. n Synaptic behavior of skyrmion-based devices, showing the number of skyrmions in the postsynapse during potentiation and depression modes under different learning stimulus densities. o Magnetic sensing using skyrmion devices, where transverse resistance (R_xy) evolves under an in-plane magnetic field (B_x) for positive and negative currents (±25 mA). Reproduced with permission from: f ref. ¹⁶⁹, 2018 American Chemical Society; g, j ref. ¹⁷⁴, Springer Nature; h ref. ¹⁷⁰, 2025 AIP Publishing LLC; i ref. ²¹⁷, 2025 IEEE; k ref. ¹⁴⁴, 2025 American Chemical Society; l, n ref. ¹⁶¹, 2017 IOP Publishing Ltd; m ref. ¹⁸³, 2025 American Association; o ref. ¹⁸², arxiv.