Highly sensitive heat flux sensor based on the transverse thermoelectric effect of YBa2Cu3O7−δ thin film

Thin film heat flux sensors with the size of 5 mm × 3 mm have been fabricated by growing c-axis tilted YBa2Cu3O7−δ thin films on miscut SrTiO3 (001) substrates. The Seebeck coefficient anisotropy between the ab-plane and the c-axis of the YBa2Cu3O7−δ thin film is utilized to generate the output voltage of the heat flux sensor via the transverse thermoelectric effect. The sensitivities of 104.9, 174.1, and 220.9 μV cm2/W have been achieved in nominal 5°, 10°, and 15° inclined thin films, respectively. Such a sensitivity of 220.9 μV cm2/W exceeds a sensitivity of 180.3 μV cm2/W from a standard and water-cooled Gardon gauge. In addition, the fast response time in the range of 15–40 ms has been identified in these sensors based on the transverse thermoelectric effect, which is significantly superior to 400 ms of the Gardon gauge. These results may provide an approach to manufacture highly sensitive heat flux sensors with a low cost, in contrast to the traditional thin film heat flux sensors with complicated micro-fabrication processes.