Evaluation of Operating Margin and Switching Probability of Voltage- Controlled Magnetic Anisotropy Magnetic Tunnel Junctions

Abstract

Voltage-controlled magnetic anisotropy (VCMA) has attracted great attention as it allows faster switching and lower energy consumption compared to traditional spin-transfer torque-based magnetization switching. In this paper, we evaluate the operating margin and switching probability of VCMA-based magnetic tunnel junctions using realistic material and device parameters. For this paper, we developed a physics-based SPICE model that incorporates various VCMA parameters such as VCMA coefficient, energy barrier, time constant, and external magnetic field. Switching probability of a VCMA device was obtained by running Monte Carlo simulations including thermal fluctuation effects. A design space exploration was performed using the proposed simulation framework. The highest switching probabilities we were able to achieve were 94.9%, 84.8%, and 53.5%, for VCMA coefficient values of 33, 105, and 290 fJ · V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> · m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , respectively. Our study shows that for VCMA devices to become viable, their switching probability must be improved significantly either through new physics or material innovation.