Spin-torque diode effect in magnetic tunnel junctions
Spin-torque diode effect in magnetic tunnel junctions
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DOI：
10.1038/nature04207
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发表时间：
2005-11-17
期刊：
影响因子：
64.8
通讯作者：
Yuasa, S
中科院分区：
文献类型：
--
作者：
Tulapurkar, AA;Suzuki, Y;Yuasa, S
目前，人们对“自旋电子”器件的开发很感兴趣，其中利用电子的自旋（而不仅仅是它们的电荷）预计将提供超越传统电子器件的新功能。一个被广泛研究的例子是，自旋极化电流对纳米级磁体的自旋力矩施加的扭矩，它的根源在于电子的自旋自由度。该扭矩导致磁矩以潜在有用的频率旋转（1-19）。在这里，我们报告了一个非常不同的现象，也是基于自旋动力学和自旋相关的运输之间的相互作用，这是从不寻常的二极管行为。我们表明，将小射频交流电应用于纳米级磁性隧道结（20-22）可以产生可测量的直流电（d.c.）当频率与自旋扭矩效应引起的自旋振荡共振时，器件两端的电压：在共振时（可以通过外部磁场进行调谐），该结构根据电流的方向表现出不同的电阻状态。这种行为明显不同于传统的半导体二极管（23）的行为，并且可以形成电信电路中的纳米级射频检测器的基础。
There is currently much interest in the development of 'spin-tronic' devices, in which harnessing the spins of electrons (rather than just their charges) is anticipated to provide new functionalities that go beyond those possible with conventional electronic devices. One widely studied example of an effect that has its roots in the electron's spin degree of freedom is the torque exerted by a spin-polarized electric current on the spin moment of a nanometre-scale magnet. This torque causes the magnetic moment to rotate(1-19) at potentially useful frequencies. Here we report a very different phenomenon that is also based on the interplay between spin dynamics and spin-dependent transport, and which arises from unusual diode behaviour. We show that the application of a small radio-frequency alternating current to a nanometre-scale magnetic tunnel junction(20-22) can generate a measurable direct-current (d.c.) voltage across the device when the frequency is resonant with the spin oscillations that arise from the spin-torque effect: at resonance (which can be tuned by an external magnetic field), the structure exhibits different resistance states depending on the direction of the current. This behaviour is markedly different from that of a conventional semiconductor diode(23), and could form the basis of a nanometre-scale radio-frequency detector in telecommunication circuits.