Induction of coherent magnetization switching in a few atomic layers of FeCo using voltage pulses
Induction of coherent magnetization switching in a few atomic layers of FeCo using voltage pulses
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DOI：
10.1038/nmat3172
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发表时间：
2012-01-01
期刊：
影响因子：
41.2
通讯作者：
Suzuki, Yoshishige
中科院分区：
文献类型：
--
作者：
Shiota, Yoichi;Nozaki, Takayuki;Suzuki, Yoshishige
金属磁体的磁化方向通常通过磁场或通过自旋电流注入到纳米尺寸的磁性单元（1，2）中来控制。这两种方法都使用电流来控制磁化方向;因此，它们都是耗能的。使用电场（3）的磁化控制被认为是期望的，因为其预期的超低功耗和相干行为。先前实现磁化切换的电压控制的实验方法已经使用了具有和不具有压电材料的单个铁磁层、铁磁半导体、多铁性材料以及它们的混合系统（4-15）。然而，使用电压信号的磁化的相干控制迄今尚未实现。此外，由于电场不会破坏时间反转对称性，因此双磁化切换（这在信息存储中是必不可少的）具有内在的困难。在这里，我们展示了一个相干的旋进磁化切换使用电场脉冲在纳米级的磁性细胞与几个原子FeCo（001）外延层相邻的MgO屏障。此外，我们还演示了利用相干进动实现双反转开关。在理想的等效开关电路中，单次开关的估计功耗可以是10（4）k（B）T的量级，这表明与自旋电流注入开关过程相比，降低因子为1/500。
The magnetization direction of a metallic magnet has generally been controlled by a magnetic field or by spin-current injection into nanosized magnetic cells(1,2). Both these methods use an electric current to control the magnetization direction; therefore, they are energy consuming. Magnetization control using an electric field(3) is considered desirable because of its expected ultra-low power consumption and coherent behaviour. Previous experimental approaches towards achieving voltage control of magnetization switching have used single ferromagnetic layers with and without piezoelectric materials, ferromagnetic semiconductors, multiferroic materials, and their hybrid systems(4-15). However, the coherent control of magnetization using voltage signals has not thus far been realized. Also, bistable magnetization switching (which is essential in information storage) possesses intrinsic difficulties because an electric field does not break time-reversal symmetry. Here, we demonstrate a coherent precessional magnetization switching using electric field pulses in nanoscale magnetic cells with a few atomic FeCo (001) epitaxial layers adjacent to a MgO barrier. Furthermore, we demonstrate the realization of bistable toggle switching using the coherent precessions. The estimated power consumption for single switching in the ideal equivalent switching circuit can be of the order of 10(4)k(B)T, suggesting a reduction factor of 1/500 when compared with that of the spin-current-injection switching process.