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Mimicking neural and synaptic computations by spintronic devices

Spin devices for Non-Boolean Computing

Research Summary

Emerging spin-devices like spin-valves and domain-wall magnets (DWM) have opened new avenues for spin-based logic design. Extensive efforts have been directed towards evolution of computation schemes that can exploit such devices for energy efficient computation. Ultra-low voltage, current-mode operation of magneto-metallic spin-torque devices can potentially be suitable for non-Boolean computation schemes like, neural networks, which involve analog processing. Thus, there is a need to explore cross-hierarchy-coherent computation paradigm that can exploit the benefits of spin-based devices while compensating for their limitations. This may include evolving hybrid design schemes, where charge-based devices supplement the spin-devices, to gain large benefits at system level. As an example, lateral spin valves (LSV) involve switching of nano-magnets using spin-polarized current injection through a metallic channel such as Cu. Such spin-torque based devices possess several interesting properties that can be exploited for ultra low power computation. Analog characteristic of spin current facilitate non-Boolean computation like majority-evaluation that can be used to model a neuron. The magneto-metallic neurons can operate at ultra low terminal voltage of ~100mV, thereby resulting in small computation power. Recently research efforts are being directed to develop spintronic device structures that can mimic the functionality of biological synapses. Such low-power, hybrid designs can be suitable for various data processing applications like cognitive computing, associative memory, Boolean/non-Boolean logic and analog and digital signal processing. Simulation results for these applications based on device-circuit co-simulation framework predict several orders of magnitude improvement in computation energy as compared to state of art CMOS design.


  1. M. Sharad, C. Augustine, G. Panagopoulos and K. Roy, “Spin Based Neuron-Synapse Unit for Ultra Low Power Programmable Computational Networks”, IEEE International Joint Conference on Neural Networks, 2012.
  2. M. Sharad, C. Augustine, G. Panagopoulos, and K. Roy, "Cognitive Computing with Spin-Based Neural Networks," ACM/IEEE Design Automation Conference, June 2012.
  3. M. Sharad, G. Panagopoulos, and K. Roy, "Spin-Neuron for Ultra Low Power Computational Hardware," Device Research Conference, June 2012. (Invited Paper)
  4. M. Sharad G. Panagopoulos, C. Augustine, and K. Roy, "Ultra Low Energy Analog Image Processing Using Spin Based Neurons," NANOARCH 8th ACM/IEEE International Symposium on Nanoscale Architectures, July 2012, Amsterdam.
  5. M. Sharad, C. Augustine, and K. Roy, "Boolean and Non-Boolean Computing with Spin Devices," International Electron Devices Meeting (IEDM), December 2012. (Invited Paper)
  6. M. Sharad, C. Augustine, G. Panagopoulos, and K. Roy. "Proposal for neuromorphic hardware using spin devices.", TECHCON 2012,  arXiv preprint arXiv:1206.3227 (Highlighted in MIT Technology Review)
  7. M. Sharad, C. Augustine, G. Panagopoulos, and K. Roy, "Spin-Based Neuron Model with Domain Wall Magnets as Synapse," IEEE Transactions on Nanotechnology, July 2012, pp. 843-853.
  8. M. Sharad, K. Yogendra, K-W. Kwon, and K. Roy, "Design Of Ultra High Density And Low Power Computational Blocks Using Nano-Magnets," IEEE International Symposium on Quality of Electronic Design (ISQED), March 2013.
  9. M. Sharad, D. Fan, and K. Roy, "Ultra Low Power Computing With Resistive Crossbar Nets Using Spin Neurons," IEEE/ACM Design Automation Conference (DAC), June 2013.
  10. K. Roy , M. Sharad, D. Fan, K. Yogendra, "Beyond Charge-Base Computing : Boolean and Non boolean Computing Using spin Devices", ISLPED, 2013. (invited tutorial)
  11. K. Roy , M. Sharad, D. Fan, K. Yogendra, "Exploring Boolean and Non Boolean Computing Using Spin torque Switches", ICCAD, 2013. (invited tutorial)
  12. M. Sharad, D. Fan, and K. Roy, "Energy Efficient Non-Boolean Computing Using Spin Neurons and Memristors", IEEE Transaction on Nanotechnology, 2013
  13. M. Sharad, and K. Roy, "Dual-Pillar Spin-Torque Oscillator for Energy Efficient Computation”, Nanoarch, 2013
  14. M. Sharad and Kaushik roy, "Ultra Low Energy Analog Computing Using Spin Devcies", SRC TECHCON, 2013
  15. M. Sharad and K. Roy, “Spin Neurons: A Possible Path to Energy-Efficient Neuromorphic  Computers”, Journal of Applied Physics, 2013
  16. M. Sharad, D. Fan, K. Yogendra, K. Roy, “Ultra-Low Power Neuromorphic Computing with Spin-Torque Devices”, Berkeley Symposium on Energy Efficient Electronic Systems, 2013
  17. M. Sharad, D. Fan, K. Yogendra, K. Roy, “Energy-Efficient and Robust Associative Computing with Electrically Coupled Dual Pillar Spin-Torque Oscillators”, Journal of Applied Physics (submitted), 2013
  18. M. Sharad, K. Yogendra and K. Roy, “ Dual-Pillar Spin-Torque Oscillator for Energy Efficient Computation”, Applied Phys. Lett, 2013 
  19. S. G. Balasubramaniam, R. Venkatesan, M. Sharad, K. Roy, Anand Raghunathan, "SPIntronic Deep Learning Engine for Large-scale Neuromorphic Computing" ISLPED, 2014.
  20. S. G. Balasubramaniam, R. Venkatesan, M. Sharad, K. Roy, Anand Raghunathan, "SPINDLE: SPINtronic Deep Learning Engine for Large-scale Neuromorphic Computing", ACM JETC, 2014.
  21. A. Sengupta, S. H. Choday, Y. Kim, K. Roy, "Spin Orbit Torque Based Electronic Neuron", Applied Physics Letters, 2015.
  22. A. Sengupta, Z. Al Azim, X. Fong, K. Roy, "Spin-Orbit Torque Induced Spike-Timing Dependent Plasticity", Applied Physics Letters, 2015. (Editor's Picks)
  23. A. Sengupta, K. Roy, "Spin-Transfer Torque Magnetic Neuron for Low Power Neuromorphic Computing", IJCNN 2015. 
  24. D. Fan, Y. Shim, A. Raghunathan, K. Roy, "STT-SNN: A Spin-Transfer Torque Based Soft-Liminting Non-Linear Neuron for Low-Power Artificial Neural Networks", IEEE Transactions on Nanotechnology, 2015.
  25. A. Sengupta, K. Yogendra, D. Fan, K. Roy, "Prospects of Efficient Neural Computing with Arrays of Magneto-metallic Neurons and Synapses", ASP-DAC 2016. (Invited Paper)
  26. A. Sengupta, P. Panda, A. Raghunathan, K. Roy, "Neuromorphic Computing Enabled By Spin-Transfer Torque Devices", VLSID 2016. (Tutorial Paper)
  27. A. Sengupta, K. Yogendra, K. Roy, "Spintronic Devices for Ultra-low Power Neuromorphic Computation", ISCAS 2016. (Invited Paper)
  28. A. Sengupta, B. Han, K. Roy, "Spin-Based Neuromimetic Computing: Deep Spiking Neural Systems", SRC TECHCON 2016. 
  29. A. Sengupta, Y. Shim, K. Roy, "Proposal for an All-Spin Artificial Neural Network: Emulating neural and synaptic functionalities through domain wall motion in ferromagnets", IEEE Transactions on Biomedical Circuits and Systems, 2016 (In Press).
  30. A. Sengupta, K. Roy, "Short-Term Plasticity and Long-Term Potentiation in Magnetic Tunnel Junctions: Towards Volatile Synapses", Physical Review Applied, 2016.
  31. A. Sengupta, P. Panda, P. Wijesinghe, Y. Kim, K. Roy, "Magnetic Tunnel Junction Mimics Stochastic Cortical Spiking Neurons", Scientific Reports, 2016.
  32. A. Sengupta, M. Parsa, B. Han, K. Roy, "Probabilistic Deep Spiking Neural Systems Enabled by Magnetic Tunnel Junction", IEEE Transactions on Electron Devices, 2016.
  33. G. Srinivasan, A. Sengupta, K. Roy, "Magnetic Tunnel Junction Based Long-Term Short-Term Stochastic Synapse for a Spiking Neural Network with On-Chip STDP Learning", Scientific Reports, 2016.
  34. D. Fan, M. Sharad, A. Sengupta, K. Roy, "Hierarchical Temporal Memory Based on Spin-Neurons and Resistive Memory for Energy-Efficient Brain-Inspired Computing", IEEE Transactions on Neural Networks and Learning Systems, 2016.
  35. A. Sengupta, K. Roy, "A Vision for All-Spin Neural Networks: A Device to System Perspective", IEEE Transactions on Circuits and Systems-I: Regular Papers, 2016. (ISCAS 2016 Special Issue)
  36. A. Sengupta, A,Banerjee, K. Roy, "Hybrid Spintronic-CMOS Spiking Neural Network With On-Chip Learning: Devices, Circuits and Systems", Physical Review Applied, 2016. (Featured in MIT Technology Review: Emerging Technology from arXiV and DoD R&E Science and Technology News Bulletin)
  37. A. Sengupta, B. Han, K. Roy, "Toward a Spintronic Deep Learning Spiking Neural Processor", BioCAS 2016.
  38. G. Srinivasan, A. Sengupta, K. Roy, "Magnetic Tunnel Junction Enabled All-Spin Stochastic Spiking Neural Network", DATE 2017. (Invited Paper)