Length Scale of the Spin Seebeck Effect
Length Scale of the Spin Seebeck Effect
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DOI：
10.1103/physrevlett.115.096602
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发表时间：
2015-08-28
影响因子：
8.6
通讯作者：
Klaeui, Mathias
中科院分区：
文献类型：
--
作者：
Kehlberger, Andreas;Ritzmann, Ulrike;Klaeui, Mathias
我们研究了室温和50 K下薄膜厚度从20 nm到50 μ m的钇铁石榴石（YIG）样品中自旋塞贝克效应的起源。我们的研究结果揭示了纵向自旋塞贝克效应振幅的绝缘亚铁磁YIG的厚度，这在一个临界厚度，随着温度的降低而增加的特性增加。观察到的行为不能解释为界面效应或材料参数的变化。热磁振子自旋电流的数值模拟的比较产生定性协议的厚度依赖于有限的磁振子传播长度。这使我们能够跟踪所观察到的信号的起源，真正的散装磁振子自旋电流由于自旋塞贝克效应排除了接口的起源，并允许我们衡量在这个系统中的热激发磁振子的到达不同的温度。在低温下，甚至定量协议与模拟。
We investigate the origin of the spin Seebeck effect in yttrium iron garnet (YIG) samples for film thicknesses from 20 nm to 50 mu m at room temperature and 50 K. Our results reveal a characteristic increase of the longitudinal spin Seebeck effect amplitude with the thickness of the insulating ferrimagnetic YIG, which levels off at a critical thickness that increases with decreasing temperature. The observed behavior cannot be explained as an interface effect or by variations of the material parameters. Comparison to numerical simulations of thermal magnonic spin currents yields qualitative agreement for the thickness dependence resulting from the finite magnon propagation length. This allows us to trace the origin of the observed signals to genuine bulk magnonic spin currents due to the spin Seebeck effect ruling out an interface origin and allowing us to gauge the reach of thermally excited magnons in this system for different temperatures. At low temperature, even quantitative agreement with the simulations is found.