[16p-S4_201-13~19] 10.3 スピンデバイス・磁気メモリ・ストレージ技術

18:15 〜 18:30奨励賞エントリー英語発表

[16p-S4_201-17] Spin-Transfer Torque Efficiency in Coupled Synthetic Free Layers Studied with Stochastic Magnetic Tunnel Junctions

〇Takuma Kinoshita¹, Mototsugu Ohtani¹, Nuno Cacoilo¹, Haruna Kaneko¹, Shun Kanai¹, Hideo Ohno¹, Shunsuke Fukami¹ (1.Tohoku Univ.)

キーワード：

magnetic tunnel junction、Synthetic antiferromagnet、Synthetic ferromagnet

Magnetic tunnel junctions (MTJs) controlled by spin-transfer torque (STT) are key elements in nonvolatile memories and have recently been explored as stochastic devices in unconventional computing. The use of ferromagnetically coupled (FC) or antiferromagnetically coupled (AFC) synthetic free layers has been proposed for these applications, as it enables tuning of device performance and reliability. Until now, the effect of STT on the dynamics of FC and AFC free layers has remained controversial, yet clarifying this issue is increasingly important as STT-MTJ technologies evolve. In this study, we show an unambiguous comparison of the STT efficiency in FC and AFC synthetic free layers enabled by measuring a time-averaged response of stochastic MTJs as a function of the applied current. Despite their distinct magnetic configurations, we find indistinguishable STT efficiency between the two structures. This result indicates that interlayer mutual torque provides a negligible contribution, while the torque from the reference layer dominates the STT effect on the synthetic free layers.