Electronic conduction in La-based perovskite-type oxides

A systematic study of La-based perovskite-type oxides from the viewpoint of their electronic conduction properties was performed. LaCo(0.5)Ni(0.5)O(3±δ) was found to be a promising candidate as a replacement for standard metals used in oxide electrodes and wiring that are operated at temperatures up to 1173 K in air because of its high electrical conductivity and stability at high temperatures. LaCo(0.5)Ni(0.5)O(3±δ) exhibits a high conductivity of 1.9 × 10(3) S cm(−1) at room temperature (R.T.) because of a high carrier concentration n of 2.2 × 10(22) cm(−3) and a small effective mass m∗ of 0.10 m(e). Notably, LaCo(0.5)Ni(0.5)O(3±δ) exhibits this high electrical conductivity from R.T. to 1173 K, and little change in the oxygen content occurs under these conditions. LaCo(0.5)Ni(0.5)O(3±δ) is the most suitable for the fabrication of oxide electrodes and wiring, though La(1−x)Sr(x)CoO(3±δ) and La(1−x)Sr(x)MnO(3±δ) also exhibit high electronic conductivity at R.T., with maximum electrical conductivities of 4.4 × 10(3) S cm(−1) for La(0.5)Sr(0.5)CoO(3±δ) and 1.5 × 10(3) S cm(−1) for La(0.6)Sr(0.4)MnO(3±δ) because oxygen release occurs in La(1−x)Sr(x)CoO(3±δ) as elevating temperature and the electrical conductivity of La(0.6)Sr(0.4)MnO(3±δ) slightly decreases at temperatures above 400 K.