Department of Physics and Astronomy, University of Denver, Denver, Colorado 80208, USA.
Phys Rev Lett. 2013 Sep 20;111(12):126602. doi: 10.1103/PhysRevLett.111.126602. Epub 2013 Sep 17.
We present direct measurements of the Peltier effect as a function of temperature from 77 to 325 K in Ni, Ni(80)Fe(20), and Fe thin films made using a suspended Si-N membrane structure. Measurement of the Seebeck effect in the same films allows us to directly test predictions of Onsager reciprocity between the Peltier and Seebeck effects. The Peltier coefficient Π is negative for both Ni and Ni(80)Fe(20) films and positive for the Fe film. The Fe film also exhibits a peak associated with the magnon drag Peltier effect. The observation of magnon drag in the Fe film verifies that the coupling between the phonon, magnon, and electron systems in the film is the same whether driven by heat current or charge current. The excellent agreement between Π values predicted using the experimentally determined Seebeck coefficient for these films and measured values offers direct experimental confirmation of the Onsager reciprocity between these thermoelectric effects in ferromagnetic thin films near room temperature.
我们展示了 Ni、Ni(80)Fe(20) 和 Fe 薄膜在 77 至 325 K 温度范围内的 Peltier 效应与温度的直接关系的测量结果，这些薄膜是使用悬浮的 Si-N 膜结构制作的。在相同的薄膜中测量 Seebeck 效应使我们能够直接检验 Peltier 效应和 Seebeck 效应之间 Onsager 互易性的预测。对于 Ni 和 Ni(80)Fe(20) 薄膜，Peltier 系数 Π 为负，而对于 Fe 薄膜，Π 为正。Fe 薄膜还表现出与磁子拖拽 Peltier 效应相关的峰值。在 Fe 薄膜中观察到磁子拖拽现象证实了无论由热流还是电流驱动，薄膜中声子、磁子和电子系统之间的耦合是相同的。这些薄膜的实验确定的 Seebeck 系数预测的 Π 值与测量值之间的极好一致性，直接证实了铁磁薄膜中这些热电效应在室温附近的 Onsager 互易性。
