A systematic study of La-based perovskite-type oxides from the viewpoint of their electronic conduction properties was performed. LaCo0.5Ni0.5O3±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. LaCo0.5Ni0.5O3±δ exhibits a high conductivity of 1.9 × 103 S cm-1 at room temperature (R.T.) because of a high carrier concentration n of 2.2 × 1022 cm-3 and a small effective mass m∗ of 0.10 me. Notably, LaCo0.5Ni0.5O3±δ exhibits this high electrical conductivity from R.T. to 1173 K, and little change in the oxygen content occurs under these conditions. LaCo0.5Ni0.5O3±δ is the most suitable for the fabrication of oxide electrodes and wiring, though La1-x Sr x CoO3±δ and La1-x Sr x MnO3±δ also exhibit high electronic conductivity at R.T., with maximum electrical conductivities of 4.4 × 103 S cm-1 for La0.5Sr0.5CoO3±δ and 1.5 × 103 S cm-1 for La0.6Sr0.4MnO3±δ because oxygen release occurs in La1-x Sr x CoO3±δ as elevating temperature and the electrical conductivity of La0.6Sr0.4MnO3±δ slightly decreases at temperatures above 400 K.
Keywords: carrier concentration; carrier mobility; effective mass; electrical conductivity; electronic conduction; relaxation time.