Phase locking of ultra-low power consumption stochastic magnetic bits induced by colored noise

Superparamagnetic tunnel junctions (STJs) are nanostructures with very low turnover barriers. The barrier height of an STJ is generally equal to the heat energy at room temperature; thus, it can oscillate automatically without external driving. Previous studies have shown that the randomness of an STJ can be driven by a subthreshold voltage. This synchronization can be adjusted using electrical noise, which is often considered as zero-field Gaussian white noise. However, the actual circuit and environment are inevitably associated with colored noise, which has not been considered previously. In this work, numerical simulations were performed to study the phase-locking characteristics of a single STJ with the aid of several typical types of colored noise. The results show that the phase-locked behavior of an STJ can be effectively enhanced by colored noise whose power spectral density per unit of bandwidth is proportional to its frequency. Meanwhile, colored noise whose power spectral density per unit of bandwidth and frequency are inversely proportional can suppress the synchronization of STJs by suppressing the increase in junction frequency. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Colored noise can affect the phase-locking characteristics of superparamagnetic tunnel junctions (STJs). Colored noise with power spectral density proportional to frequency can enhance synchronization, while colored noise with power spectral density inversely proportional to frequency can suppress synchronization.