Thermoelectric properties of Pr-substituted YBCO ceramics

Abstract

The thermoelectric properties of Pr-substituted YBCO ceramics were investigated from room temperature to 773 K. The ceramics of (PrxY1−x)1.06Ba1.94Cu3O7−y ((PrxY1−x)BCO) where x = 0–1 were successfully prepared by a conventional sintering method at 920 °C for 12 h in normal air atmosphere. Phase identification was carried out by X-ray diffraction (XRD) technique. The microstructure of samples was studied using scanning electron microscopy (SEM). The thermogravimetric and differential thermal analyses (TG/DTA) were used to examine the thermal properties of samples. In addition, electrical resistivity, Seebeck coefficient, and thermal conductivity were investigated and discussed. The average phonon velocity was measured using the Pulse-echo technique at room temperature to discuss the substitution effect on the lattice thermal conductivity. It was observed that the substitution of Pr in YBa2Cu3O7−y improved the Seebeck coefficient (α) and showed higher figure of merit values at a wide temperature range from 298 to 773 K compared to those of pure YBCO. These results suggested that Pr substitution was a promising approach for improving thermoelectric properties of YBCO-based compounds. This suggests that, when optimized, the YBCO-based materials could show high potential for intermediate and high-temperature thermoelectric applications.