Fabrication of multilayered oxide thermoelectric modules by electrophoretic deposition under high magnetic fields

The authors report the fabrication of grain-aligned [Ca2CoO3−δ]0.62CoO2 (Ca349) thick films and a multilayered thermoelectric unicouple of Ca349 and Ca0.9La0.1MnO3−δ (Mn113) using electrophoretic deposition (EPD) and magnetic alignment methods. Strongly c-axis-oriented Ca349 thick films were obtained by EPD performed under magnetic fields. In addition, the c axis of grains was found to always align parallel to the direction of field, independently of the EPD cell configuration. The required conditions for magnetic grain alignment of fine Ca349 powders were quantitatively discussed based on magnetization anisotropy. An α-Al2O3∕Mn113∕α-Al2O3∕Ca349∕α-Al2O3 multilayered thick film was successfully developed.