Observation of the spin Seebeck effect
Observation of the spin Seebeck effect
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DOI：
10.1038/nature07321
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发表时间：
2008-10-09
期刊：
影响因子：
64.8
通讯作者：
Saitoh, E.
中科院分区：
文献类型：
--
作者：
Uchida, K.;Takahashi, S.;Saitoh, E.
通过在温度梯度中放置导体而产生的电压称为塞贝克效应(1，2)。其效率由塞贝克系数S表示，该系数定义为产生的电压与温差的比率，并由散射率和传导电子的密度决定。例如，在热力发电机中可以利用这种效应，通过连接两个具有不同塞贝克系数的导体来进行温度传感，这种装置被称为热电偶(1，2)。在这里，我们报道了电子自旋驱动功率或电压的热产生：自旋塞贝克效应。利用最近发展起来的包含自旋霍尔效应的自旋探测技术(3-14)，我们测量了金属磁体中温度梯度产生的自旋电压。这种热感应自旋电压即使在远离样品末端的地方也会持续存在，只需将金属附着在磁体上，就可以从磁体上的每个位置提取自旋。这里观察到的自旋塞贝克效应直接适用于自旋电压发生器的生产，而自旋电压发生器是驱动自旋电子器件(15-18)的关键。自旋塞贝克效应允许我们在很长的距离上通过纯自旋电流(19)，即没有电流的电子自旋的流动。这些创新能力将为自旋电子学研究注入活力。
The generation of electric voltage by placing a conductor in a temperature gradient is called the Seebeck effect(1,2). Its efficiency is represented by the Seebeck coefficient, S, which is defined as the ratio of the generated electric voltage to the temperature difference, and is determined by the scattering rate and the density of the conduction electrons. The effect can be exploited, for example, in thermal electric- power generators and for temperature sensing, by connecting two conductors with different Seebeck coefficients, a device called a thermocouple(1,2). Here we report the observation of the thermal generation of driving power, or voltage, for electron spin: the spin Seebeck effect. Using a recently developed spin-detection technique that involves the spin Hall effect(3-14), we measure the spin voltage generated from a temperature gradient in a metallic magnet. This thermally induced spin voltage persists even at distances far from the sample ends, and spins can be extracted from every position on the magnet simply by attaching a metal. The spin Seebeck effect observed here is directly applicable to the production of spin- voltage generators, which are crucial for driving spintronic(15-18) devices. The spin Seebeck effect allows us to pass a pure spin current(19), a flow of electron spins without electric currents, over a long distance. These innovative capabilities will invigorate spintronics research.