Enhanced Transverse Thermoelectric Voltage in the Au/Ni Foil Bilayer System via the Combination of Spin Seebeck Effect and Anomalous Nernst Effect

Abstract

The transverse thermoelectric voltage in the Au/Ni foil bilayer system has been investigated due to the combination of the spin Seebeck effect (SSE) and the anomalous Nernst effect (ANE) at room temperature. It is found that the transverse thermoelectric voltage proportionally increases with increasing applied temperature difference and approaches a constant value when the magnetization of the Ni foil reaches a saturation state. The measured thermoelectric voltage signal, about 0.424 ± 0.005 μV at 5 K of temperature difference, is the combination of the ANE signal from the Ni foil and the SSE signal from the Au/Ni foil bilayer system. The SSE and ANE coefficients are determined from the observed voltages, temperature difference, and dimension of the sample. Consequently, the SSE coefficient is found to be 2.5 times larger than the ANE coefficient. Moreover, the special dimensionless figure of merit for SSE is much greater than the obtained from ANE about 7 times. The work demonstrates the enhancement of the thermoelectric voltage due to the superposition of the SSE and ANE in the single bilayer system.