Ca3Co4O9/polycrystalline Al2O3: an effective template for c-axis oriented layered cobaltate thin films by chemical solution deposition

Abstract

In this paper, Bi₂Sr₂Co₂O_y and Bi₂Ba₂Co₂O_y thin films were prepared on Ca₃Co₄O₉/polycrystalline Al₂O₃ thin films by chemical solution deposition. The results show that both of the bismuth-based cobaltate thin films are self-assembled c-axis oriented, which confirms that Ca₃Co₄O₉/polycrystalline Al₂O₃ thin film can be used as an effective template to induce c-axis oriented grain growth in layered cobaltate thin films. The annealing temperature effects on Bi₂Sr₂Co₂O_y thin films were investigated, and the resistivity and Seebeck coefficient decrease with the increasing annealing temperature. The results will provide an effective template to realize self-assembled c-axis oriented layered cobaltate thin films on polycrystalline substrates by chemical solution deposition.