Hitachi Cambridge Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
Nat Mater. 2013 Sep;12(9):808-14. doi: 10.1038/nmat3657. Epub 2013 Jun 9.
The rich internal degrees of freedom of magnetic domain walls make them an attractive complement to electron charge for exploring new concepts of storage, transport and processing of information. Here we use the tunable internal structure of a domain wall in a perpendicularly magnetized GaMnAsP/GaAs ferromagnetic semiconductor and demonstrate devices in which piezoelectrically controlled magnetic anisotropy yields up to 500% mobility variations for an electrical-current-driven domain wall. We observe current-induced domain wall motion over a wide range of current-pulse amplitudes and report a direct observation and the piezoelectric control of the Walker breakdown separating two regimes with different mobilities. Our work demonstrates that in spin-orbit-coupled ferromagnets with weak extrinsic domain wall pinning, the piezoelectric control allows one to experimentally assess the upper and lower boundaries of the characteristic ratio of adiabatic and non-adiabatic spin-transfer torques in the current-driven domain wall motion.
磁畴壁丰富的内部自由度使它们成为探索信息存储、传输和处理新概念的电子电荷的理想补充。在这里，我们利用垂直磁化 GaMnAsP/GaAs 铁磁半导体中畴壁的可调内部结构，展示了在这些器件中，通过压电控制磁各向异性，可使电流驱动的畴壁的迁移率变化高达 500%。我们观察到电流诱导畴壁在宽范围的电流脉冲幅度内运动，并报告了直接观察和压电控制 Walker 击穿，该击穿将具有不同迁移率的两个区域分开。我们的工作表明，在具有弱外部分畴壁钉扎的自旋轨道耦合铁磁体中，压电控制允许人们在实验上评估电流驱动畴壁运动中绝热和非绝热自旋转移力矩的特征比的上限和下限。
