Thermoelectric Properties of Nano-structure Controlled Sm2−xCexCuO4 Thin Films

Abstract

ABSTRACTSm2−xCexCuO4 (SCCO) is well known as an n-type superconductor with large physical anisotropies. In order to enhance the thermoelectric conversion performance, we have prepared the SCCO epitaxial films and controlled a crystallographic orientation, a carrier concentration and an introduction of nano-structures. The SCCO films and nano-structures consisting of CeO2 were fabricated using pulsed laser deposition method on SrTiO3 single crystalline substrates. Due to the orientation control and the optimization of carrier concentration, a low resistivity and a high Seebeck coefficient were achieved, and a power factor (PF) reached 1.14×10−3 W/mK2 at 323 K in the SCCO film with x × = 0.02. In addition, we measured the nano-structural effect on the PF of SCCO films. As a result, the PF showed a maximum in the film on a certain shape of the nano-structures. We speculate that the low resistivity was achieved by a formation of high Ce concentration layer near the interface between film and nano-structure.