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Implementation of a Binary Neural Network on a Passive Array of Magnetic Tunnel Junctions



Jonathan Goodwill, Nitin Prasad, Brian Hoskins, Matthew Daniels, Advait Madhavan, Lei Wan, Tiffany Santos, Michael Tran, Jordan Katine, Patrick Braganca, Mark Stiles, Jabez J. McClelland


The increasing scale of neural networks and their growing application space have produced a demand for more energy and memory efficient artificial-intelligence-specific hardware. Avenues to mitigate the main issue, the von Neumann bottleneck, include in-memory and near-memory architectures, as well as algorithmic approaches. Here we leverage low-power and the inherently binary operation of magnetic tunnel junctions (MTJs) to realize the first neural network hardware inference accelerator based on passive arrays of MTJs. In general, transferring a trained network model to hardware for inference is confronted by degradation in performance due to nonidealities in the substrate, parasitic resistance, device to device variations, and write errors. To quantify the effect of device non-idealities, we benchmark 300 unique weight matrix solutions of a 2-layer perceptron to classify the Wine dataset for both classification accuracy and write fidelity. Despite device imperfections, we achieve software-equivalent accuracy of up to 95.3 % with proper tuning of network parameters in 15 × 15 MTJ arrays having a range of device sizes. The success of this tuning process shows that new metrics are needed to characterize the performance and quality of networks reproduced in mixed signal hardware.
Physical Review Applied


neural network, magnetic tunnel junction, artificial intelligence, crossbar array


Goodwill, J. , Prasad, N. , Hoskins, B. , Daniels, M. , Madhavan, A. , Wan, L. , Santos, T. , Tran, M. , Katine, J. , Braganca, P. , Stiles, M. and McClelland, J. (2022), Implementation of a Binary Neural Network on a Passive Array of Magnetic Tunnel Junctions, Physical Review Applied, [online],, (Accessed June 14, 2024)


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Created July 18, 2022, Updated November 29, 2022