Time-resolved nanosecond magnetization switching induced by spin-transfer torque for cryogenic memories

Abstract

Spin-transfer torque magnetic random access memory (STT-MRAM) has emerged as a promising candidate for cryogenic data storage, owing to its nonvolatility, high density, low power consumption, and especially its nanosecond writing speed. However, the temperature dependence of the dynamics of its writing process remains unclear, hindering further optimization. Here, we investigate nanosecond STT switching dynamics in perpendicular magnetic tunnel junctions using time-resolved measurements from room temperature down to 10 K. We find that both the incubation time and the transition time exhibit certain temperature dependence, indicating that thermal effects influence not only the nucleation process preceding reversal but also the subsequent domain wall motion. Especially, the incubation time exhibits strong temperature dependence in the thermally activated regime, consistent with enhanced thermal assistance for nucleation at higher temperatures. In contrast, the incubation time becomes less temperature dependent in the precessional regime, reflecting a transition to a more deterministic switching behavior. These findings offer valuable insight into the switching dynamics and benefit the optimization of STT-MRAM performance in cryogenic memory applications.