Single-shot dynamics of spin-orbit torque and spin transfer torque switching in three-terminal magnetic tunnel junctions
Single-shot dynamics of spin-orbit torque and spin transfer torque switching in three-terminal magnetic tunnel junctions
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DOI：
10.1038/s41565-019-0607-7
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发表时间：
2020-01-27
影响因子：
38.3
通讯作者：
Gambardella, Pietro
中科院分区：
文献类型：
--
作者：
Grimaldi, Eva;Krizakova, Viola;Gambardella, Pietro
电流感应的自旋转移扭矩 (STT) 和自旋轨道扭矩 (SOT) 能够实现非易失性磁性随机存取存储器中磁性隧道结 (MTJ) 的电切换。为了开发更快的存储设备，需要改进电流驱动磁化动力学的时间尺度。在这里，我们报告了三端 MTJ 器件中由 SOT 驱动的磁化反转的全电时间分辨测量。电流注入期间 MTJ 电阻的单次测量表明，SOT 切换涉及随机两步过程，由域成核时间和传播时间组成，与 STT 切换相比，它们具有不同的成因、时间尺度和统计分布。我们进一步表明，SOT、STT 和磁各向异性电压控制的结合可以实现可重复的亚纳秒切换，且累积切换时间的扩展小于 0.2 ns。我们的测量揭示了 SOT、STT 和磁各向异性电压控制在确定 MTJ 器件的开关速度和效率方面的综合影响。需要磁隧道结的快速全电开关来改进下一代非易失性存储器。通过对开关动态的实时观察发现，自旋轨道扭矩、自旋转移扭矩和磁各向异性电压控制的结合使得开关延迟小于 0.2 ns。
Current-induced spin-transfer torques (STT) and spin-orbit torques (SOT) enable the electrical switching of magnetic tunnel junctions (MTJs) in non-volatile magnetic random access memories. To develop faster memory devices, an improvement in the timescales that underlie the current-driven magnetization dynamics is required. Here we report all-electrical time-resolved measurements of magnetization reversal driven by SOT in a three-terminal MTJ device. Single-shot measurements of the MTJ resistance during current injection reveal that SOT switching involves a stochastic two-step process that consists of a domain nucleation time and propagation time, which have different genesis, timescales and statistical distributions compared to STT switching. We further show that the combination of SOT, STT and the voltage control of magnetic anisotropy leads to reproducible subnanosecond switching with the spread of the cumulative switching time smaller than 0.2 ns. Our measurements unravel the combined impact of SOT, STT and the voltage control of magnetic anisotropy in determining the switching speed and efficiency of MTJ devices.Fast all-electrical switching of magnetic tunnel junctions is required to improve the next generation of non-volatile memory. The combination of spin-orbit torques, spin-transfer torques, and the voltage control of magnetic anisotropy permits switching latency smaller than 0.2 ns as unveiled by real-time observation of the switching dynamics.