Critical suppression of spin Seebeck effect by magnetic fields
Critical suppression of spin Seebeck effect by magnetic fields
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DOI：
10.1103/physrevb.92.064413
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发表时间：
2015-08-10
影响因子：
3.7
通讯作者：
Saitoh, Eiji
中科院分区：
文献类型：
--
作者：
Kikkawa, Takashi;Uchida, Ken-ichi;Saitoh, Eiji
研究了Pt/Y_3Fe_5O_（12）（YIG）结系统在不同磁场和温度下的纵向自旋塞贝克效应（LSSE）。我们发现，LSSE电压在Pt/YIG板系统被抑制，通过施加高磁场，这种抑制是在低温下的关键增强。在室温附近，Pt/YIG板系统中的场诱导LSSE抑制太大，不能简单地通过考虑磁振子激发中的塞曼能隙的影响来解释。这一结果要求我们引入一个磁振子频率依赖机制的情况下，LSSE的低频磁振子占主导地位的贡献。通过改变YIG的厚度，观察到的磁场依赖性的LSSE电压的变化，这表明由低频磁振子的热自旋转换被抑制在薄的YIG薄膜由于这种磁振子的长的特征长度。
The longitudinal spin Seebeck effect (LSSE) in Pt/Y3Fe5O12 (YIG) junction systems has been investigated at various magnetic fields and temperatures. We found that the LSSE voltage in a Pt/YIG-slab system is suppressed by applying high magnetic fields and this suppression is critically enhanced at low temperatures. The field-induced suppression of the LSSE in the Pt/YIG-slab system is too large at around room temperature to be explained simply by considering the effect of the Zeeman gap in magnon excitation. This result requires us to introduce a magnon-frequency-dependent mechanism into the scenario of LSSE; low-frequency magnons dominantly contribute to the LSSE. The magnetic field dependence of the LSSE voltage was observed to change by changing the thickness of YIG, suggesting that the thermospin conversion by the low-frequency magnons is suppressed in thin YIG films due to the long characteristic lengths of such magnons.