Electronic conduction in La-based perovskite-type oxides

Abstract

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−xSrxCoO3±δ and La1−xSrxMnO3±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−xSrxCoO3±δ as elevating temperature and the electrical conductivity of La0.6Sr0.4MnO3±δ slightly decreases at temperatures above 400 K.

Structural, optical, thermoelectrical, and magnetic study of Zn1‐xCoxO (0 ≤ x ≤ 0.10) nanocrystals

“…Although the difference in the ionic radii of Co 2+ ions and Zn 2+ ions is very small, Co doping into the ZnO lattice can induce a strain in it and lead to the distortion of the ZnO unit cell . It can be concluded that because of increasing the bond length by a level of doping of 2%, the heat conductivity decreases, whereas the electric conductivity increases, resulting in an increase in charge carriers, and finally, the thermoelectric conversion efficiency (ZT) increases for this system, which makes it possible to use them for thermoelectric applications. The lattice parameters are briefly described in Table .…”

Structural and morphological alterations induced by cobalt substitution in LaMnO3 perovskites

“…In those structures, the octahedral BO6 presents both distortion and rotation that are more important when smaller A-site cations are used. This increases the electrical resistivity and therefore the overall catalytic activity toward oxygen reduction is affected [5,26]. In octahedral BO6 each cation is surrounded by six oxygen anions and, according to the crystal field theory (CFT), d-orbitals split into a lower group of three t2g and a highest group of two eg energy orbitals [27].…”

Structural, Dielectric, and Energy Storage Properties of Citric Acid and Ethylene Glycol Assisted Hydrothermally Synthesized Y2FeCoO6

“…The high ionic radius of lanthanum leads to the formation of cubic or a rhombohedral phase, which is considered good for electronic conduction. [ 53,54 ]…”