Selectivity Enhancement in Quasi-Two-Terminal SOT Structures via Double-Pulse Writing

Abstract Spin–orbit torque (SOT) magnetic tunnel junctions employ decoupled read/write paths, offering the advantage of high endurance. Designing multiple pillars with a shared SOT track enables further area savings in SOT devices. In such quasi-two-terminal SOT devices, a vertical-voltage-based selective operation is employed as an alternative to CMOS gating. However, high-volume experimental data on the selectivity of quasi-two-terminal SOT devices remain limited, as selectivity cannot be predicted owing to the complexity arising from nonideal factors. This study evaluates selectivity through extensive experimental testing, with detailed rate curves also provided. To the best of our knowledge, this is the first report describing the degradation of selectivity caused by the ballooning effect. To enhance selectivity, double-pulse writing is proposed and demonstrated, resulting in improved write error rate curves. The findings of this study are crucial for the practical implementation of quasi-two-terminal SOT devices in memory applications and provide experimental guidance for application layers such as circuit design.