Magnetic Stochastic Oscillators: Noise-Induced Synchronization to Underthreshold Excitation and Comprehensive Compact Model

Superparamagnetic tunnel junctions (SMTJs) are noise powered stochastic oscillators, which can harness thermal energy through phenomena such as stochastic resonance and noise-induced synchronization. This enables them to operate with the minimal externally supplied energy, and therefore, makes them promising candidates for implementing bioinspired computing schemes. These applications require understanding how SMTJs can be integrated into CMOS circuits. In this paper, we present a compact model of SMTJ, written in the VerilogA language, that can be used within standard integrated circuit design tools. This compact model is based on the Néel-Brown model and allows for fast simulations. We show that this model can reproduce the experimental characterization of a sample subjected to different values of dc currents. Then, we definitively demonstrate the validity of the model by confronting it to the experimental results in the case of a complex phenomenon: noise-induced synchronization.