Thermally driven spin injection from a ferromagnet into a non-magnetic metal
Thermally driven spin injection from a ferromagnet into a non-magnetic metal
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DOI：
10.1038/nphys1767
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发表时间：
2010-11-01
期刊：
影响因子：
19.6
通讯作者：
van Wees, B. J.
中科院分区：
文献类型：
--
作者：
Slachter, A.;Bakker, F. L.;van Wees, B. J.
自旋极化载流子的产生、操纵和检测是基于自旋的电子学的关键要素（1，2）。大多数实际的装置（3-5）使用垂直几何形状，其中自旋电流伴随有电荷电流。近年来，纯自旋电流的新来源（即没有电荷电流的自旋角动量的输运）已经被证明（6-9）和应用（10-12）。在这里，我们展示了一个概念上的纯自旋电流的新来源驱动的热流动之间的铁磁体和非磁性金属的界面。这种自旋电流的产生是因为，在铁磁体中，塞贝克效应--描述了由于温度梯度而产生的电压--是自旋相关的（13，14）。我们在非局部横向几何中实验研究了这种新的自旋电流源，并开发了一个三维模型，该模型描述了这种几何中的热量，电荷和自旋输运，使我们能够量化这一过程（15）。我们获得了坡莫合金的自旋相关Seebeck系数为-3.8 μ VK-1，表明热驱动自旋注入是电自旋注入的可行替代方案，例如，自旋转移扭矩实验（16）。
Creation, manipulation and detection of spin-polarized carriers are the key elements of spin-based electronics(1,2). Most practical devices(3-5) use a perpendicular geometry in which the spin currents are accompanied by charge currents. In recent years, new sources of pure spin currents ( that is, transport of spin angular momentum without charge currents) have been demonstrated(6-9) and applied(10-12). Here we demonstrate a conceptually new source of pure spin current driven by the flow of heat across the interface between a ferromagnet and a non-magnetic metal. This spin current is generated because, in a ferromagnet, the Seebeck effect-which describes the generation of a voltage as a result of a temperature gradient-is spin dependent(13,14). We studied this new source of spin currents experimentally in a non-local lateral geometry and developed a three-dimensional model that describes the heat, charge and spin transport in this geometry, enabling us to quantify this process(15). We obtain a spin-dependent Seebeck coefficient for Permalloy of -3.8 mu VK-1, suggesting that thermally driven spin injection is a feasible alternative for electrical spin injection in, for example, spin-transfer-torque experiments(16).