Magnetic field dependence of the nonlocal spin Seebeck effect in Pt/YIG/Pt systems at low temperatures
Magnetic field dependence of the nonlocal spin Seebeck effect in Pt/YIG/Pt systems at low temperatures
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DOI：
10.1063/1.5135944
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发表时间：
2019-10
期刊：
影响因子：
1.6
通讯作者：
K. Oyanagi;T. Kikkawa;E. Saitoh
中科院分区：
文献类型：
--
作者：
K. Oyanagi;T. Kikkawa;E. Saitoh
本文报道了Pt/Y3 Fe 5 O 12（YIG）/Pt系统在不同温度T（3 K <T <30 0 K）下横向组态的非定域自旋Seebeck效应（nlSSE）随磁场B（最高可达10 T）的变化. nlSSE电压随着$B$的增加而减小，与输入功率（施加的充电电流的平方$I^2$）成线性关系。当塞曼能量在低温下超过热能时，nlSSE的降低变得显著，这可以被解释为与nlSSE相关的磁振子的冻结。此外，我们发现的非线性功率依赖的nlSSE与增加$I$在低温（$T$ < 20 K），在该$B$诱导的信号减少变得不太明显。我们的实验结果表明，在非线性制度的高能量磁振子的人口超过预期的热能。我们还估计了磁振子自旋扩散长度作为B和T的函数。
We report the nonlocal spin Seebeck effect (nlSSE) in a lateral configuration of Pt/Y$_3$Fe$_5$O$_{12}$(YIG)/Pt systems as a function of the magnetic field $B$ (up to 10 T) at various temperatures $T$ (3 K < $T$ < 300 K). The nlSSE voltage decreases with increasing $B$ in a linear regime with respect to the input power (the applied charge-current squared $I^2$). The reduction of the nlSSE becomes substantial when the Zeeman energy exceeds thermal energy at low temperatures, which can be interpreted as freeze-out of magnons relevant for the nlSSE. Furthermore, we found the non-linear power dependence of the nlSSE with increasing $I$ at low temperatures ($T$ < 20 K), at which the $B$-induced signal reduction becomes less visible. Our experimental results suggest that in the non-linear regime high-energy magnons are over populated than those expected from the thermal energy. We also estimate the magnon spin diffusion length as functions of $B$ and $T$.