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arXiv · 2312.03352

Large Non-Volatile Frequency Tuning of Spin Hall Nano-Oscillators using Circular Memristive Nano-Gates

Maha Khademi·Akash Kumar·Mona Rajabali·Saroj P. Dash·Johan Åkerman
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Abstract

Spin Hall nano oscillators (SHNOs) are promising candidates for neuromorphic computing due to their miniaturized dimensions, non-linearity, fast dynamics, and ability to synchronize in long chains and arrays. However, tuning the individual SHNOs in large chains/arrays, which is key to implementing synaptic control, has remained a challenge. Here, we demonstrate circular memristive nano-gates, both precisely aligned and shifted with respect to nano-constriction SHNOs of W/CoFeB/HfOx, with increased quality of the device tunability. Gating at the exact center of the nano-constriction region is found to cause irreversible degradation to the oxide layer, resulting in a permanent frequency shift of the auto-oscillating modes. As a remedy, gates shifted outside of the immediate nano-constriction region can tune the frequency dramatically (>200 MHz) without causing any permanent change to the constriction region. Circular memristive nano-gates can, therefore, be used in SHNO chains/arrays to manipulate the synchronization states precisely over large networks of oscillators.

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Maha Khademi, Akash Kumar, Mona Rajabali, Saroj P. Dash, Johan Åkerman. 2023-12-06. Large Non-Volatile Frequency Tuning of Spin Hall Nano-Oscillators using Circular Memristive Nano-Gates. https://doi.org/10.1109/led.2023.3339218

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