The effects of dopant valence on the structure and electrical conductivity of LaInO3

The effects on the structure and electrical conduction behavior of strontium and zirconium doped LaInO3 was studied in this paper. XRD and Raman spectra both confirm that Sr and Zr cations are substitutionally introduced to the La- and In-sites to a certain limitation respectively. Cation vacancies may be the most likely point defects for ZrO2-doped LaInO3 perovskite oxide (LaIn0.9Zr0.1O3+delta), which leads to the decrease of oxygen-ion conductivity, while Sr doping (La0.9Sr0.1InO3-delta) produces oxygen vacancies and will greatly enhance the electrical conductivity of LalnO(3). When Sr and Zr were co-doped with the same concentration (La0.9Sr0.1In0.9Zr0.1O3), the effects of Sr doping will be partially eliminated by Zr doping resulting in a relatively low electrical conductivity. When Sr-doping level increases further (La0.8Sr0.2In0.9Zr0.1O3-delta), its conduction behaves the same as that of La0.9Sr0.1InO3-delta since they are dominated by the same acceptor doping (10 mol%). Both La0.8Sr0.2In0.9Zr0.1O3-delta and La0.9Sr0.1InO3-delta show three different conduction regions, that is, p-type at high P-O2, n-type at low P-O2 and P-O2-independent conduction at intermediate oxygen partial pressure while only p-type conduction appears for La0.9Sr0.1In0.9Zr0.1O3 at high PO2, and LaIn0.9Zr0.1O3+delta shows an entirely different conduction behavior in the measured oxygen partial pressures. (C) 2001 Elsevier Science Ltd. All rights reserved.