SKYRMION DYNAMICS IN MAGNETO-OPTICAL TRACKS OF ULTRA-THIN Si(111)/CoFeB/MgO/CoFeB JUNCTIONS

Аннотация

Topologically protected spin textures, such as magnetic skyrmions, have shown the
potential for high-density data storage and energy-efficient computing applications owing to their particle
like behavior, small size, and low driving current requirements. Evaluating the writing and reading of the
skyrmion’s magnetic and electrical characteristics is crucial to implementing these devices. In this paper, we
present the magnetic heterostructure Hall bar device and study the anomalous Hall and topological Hall
signals in these devices. Using different measurement techniques, we investigate the magnetic and electrical
characteristics of the magnetic structure. We measure the skyrmion topological resistivity and the magnetic
field at different temperatures. MFM imaging and micromagnetic simulations further explain the anomalous
Hall and topological Hall resistivity characteristics at various magnetic fields and temperatures. The study
is extended to propose a skyrmion-based synaptic device showing spin-orbit torquecontrolled plasticity. The
resistance states are read using the anomalous Hall measurement technique. The device integration in a
neuromorphic circuit is simulated in a 3-layer feedforward artificial neural network ANN. Based on the
proposed synapses, the neural network is trained and tested on the MNIST data set, where a recognition
accuracy performance of about 90% is achieved. Considering the nanosecond reading/writing time scale
and a good system level performance, these devices exhibit a substantial prospect for energy-efficient
neuromorphic computing.