Arisaka Taichi, Otsuka Mioko, Hasegawa Yasuhiro
Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
Rev Sci Instrum. 2019 Apr;90(4):046104. doi: 10.1063/1.5079832.
The thermal conductivity (κ) and specific heat (C) of a thermoelectric element consisting of BiTe (SRM 3451) were obtained by impedance spectroscopy and using only electrometric measurements. The dimensionless figure of merit (zT) was successfully estimated by the four-probe method from the frequency dependence of the impedance, and the result was compared with that obtained using the two-probe method. The calculated values of zT and resistivity were 0.577 and 13.4 µΩ m, respectively, at 300 K, which allowed us to obtain κ = 2.11 W/(m K) and C = 165 J/(kg K) by using a Seebeck coefficient of -233 µV/K, a thermal diffusivity of 1.68 mm/s, and a mass density of 7.60 g/cm from our earlier electrometric measurements. The calculated κ and C are quite reasonable when compared to reported values. We thus conclude that, without relying on calorimetric measurements, impedance spectroscopy is a powerful technique for determining not only zT but also the thermal properties of thermoelectric materials via the Peltier effect.
通过阻抗谱法并仅使用静电测量，获得了由BiTe（SRM 3451）组成的热电元件的热导率（κ）和比热容（C）。通过四探针法根据阻抗的频率依赖性成功估算了无量纲品质因数（zT），并将结果与使用两探针法获得的结果进行了比较。在300 K时，zT和电阻率的计算值分别为0.577和13.4 μΩ·m，根据我们早期的静电测量，利用-233 μV/K的塞贝克系数、1.68 mm/s的热扩散率和7.60 g/cm³的质量密度，由此我们得到κ = 2.11 W/(m·K)和C = 165 J/(kg·K)。与报道值相比，计算得到的κ和C相当合理。因此，我们得出结论，无需依赖量热测量，阻抗谱法不仅是一种确定zT的强大技术，而且还能通过珀尔帖效应确定热电材料的热性能。
