Bilayer Synthetic Antiferromagnetic Skyrmion-Based Muller C-Element

Magnetic skyrmions have emerged as promising candidates for computing and storage applications owing to their ability to behave as a particle that can be created, moved, and annihilated. However, the skyrmion Hall effect (SkHE) limits their practical application by pushing them toward the edge of the patterned device, often annihilating them. Recently, it has been demonstrated that SkHE can be suppressed in an antiferromagnetically exchange-coupled bilayer system, and skyrmions can move in a straight trajectory with higher velocities without losing information enabling reliable logic and memory devices. In this work, for the first time, we propose the application of notches in such synthetic antiferromagnetic (SAF) racetracks to implement the functionality of a digital latch. Furthermore, the proposed device is used to develop a Muller C-element, which can be used for Bayesian inference and asynchronous pipelines. For a proof-of-concept demonstration, we perform micromagnetic simulations of this SAF racetrack with notches and develop a compact Verilog-A model for the device. The circuit-level simulations of the Muller C-element are performed using the compact model. Furthermore, we also propose a novel read/write circuitry for the Muller C-element utilizing the Arizona State Predictive PDK (ASAP) 7-nm CMOS technology process design kit (PDK) from ARM. Our comprehensive analysis of the performance metrics of the proposed Muller C-element based on the skyrmions on an SAF racetrack with notches clearly indicates significant benefits over conventional and CMOS-based implementations.