Tunnel-barrier-enhanced dc voltage signals induced by magnetization dynamics in magnetic tunnel junctions
Tunnel-barrier-enhanced dc voltage signals induced by magnetization dynamics in magnetic tunnel junctions
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DOI：
10.1103/physrevb.78.020401
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发表时间：
2008-07-01
影响因子：
3.7
通讯作者：
Xiao, John Q.
中科院分区：
文献类型：
--
作者：
Tserkovnyak, Yaroslav;Moriyama, T.;Xiao, John Q.
我们从理论上研究了最近观察到的磁性隧道结中磁化旋进产生的隧道势垒增强的直流电压信号。虽然自旋泵被抑制的高隧穿阻抗，两个互补的过程被预测，导致在铁磁（F）垂直棒绝缘体（I）垂直棒正常金属（N）和F垂直棒I垂直棒F结与一个铁磁共振激发相当大的电压产生。F垂直杆I垂直杆F系统中的磁动力学引起鲁棒的电荷泵浦，在开路中转化为电压。此外，在一个单一的铁磁层的动态发展纵向自旋积累内的铁磁体。然后，隧道势垒充当非侵入式探针，将自旋累积转换为可测量的电压。所提出的机制都没有受到自旋弛豫的影响，自旋弛豫通常在指数慢隧穿速率的尺度上是快的。然而，纵向自旋积累的建立，是非常敏感的自旋弛豫图片的唯象成分。
We theoretically study the recently observed tunnel-barrier-enhanced dc voltage signals generated by magnetization precession in magnetic tunnel junctions. While the spin pumping is suppressed by the high tunneling impedance, two complementary processes are predicted to result in a sizable voltage generation in ferromagnet (F)vertical bar insulator (I)vertical bar normal metal (N) and F vertical bar I vertical bar F junctions with one ferromagnet being resonantly excited. Magnetic dynamics in F vertical bar I vertical bar F systems induce a robust charge pumping, translating into voltage in open circuits. In addition, dynamics in a single ferromagnetic layer develop longitudinal spin accumulation inside the ferromagnet. A tunnel barrier then acts as a nonintrusive probe that converts the spin accumulation into a measurable voltage. Neither of the proposed mechanisms suffers from spin relaxation, which is typically fast on the scale of the exponentially slow tunneling rates. The longitudinal spin-accumulation buildup, however, is very sensitive to the phenomenological ingredients of the spin-relaxation picture.