The effects of dopant valence on the structure and electrical conductivity of LaInO 3

Abstract

The effects on the structure and electrical conduction behavior of strontium and zirconium doped LaInO 3 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 ZrO 2-doped LaInO 3 perovskite oxide (LaIn 0.9Zr 0.1O 3+ δ ), which leads to the decrease of oxygen-ion conductivity, while Sr doping (La 0.9Sr 0.1InO 3− δ ) produces oxygen vacancies and will greatly enhance the electrical conductivity of LaInO 3. When Sr and Zr were co-doped with the same concentration (La 0.9Sr 0.1In 0.9Zr 0.1O 3), 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 (La 0.8Sr 0.2In 0.9Zr 0.1O 3− δ ), its conduction behaves the same as that of La 0.9Sr 0.1InO 3− δ since they are dominated by the same acceptor doping (10 mol%). Both La 0.8Sr 0.2In 0.9Zr 0.1O 3− δ and La 0.9Sr 0.1InO 3− δ show three different conduction regions, that is, p-type at high P O 2 , n-type at low P O 2 and P O 2 -independent conduction at intermediate oxygen partial pressure while only p-type conduction appears for La 0.9Sr 0.1In 0.9Zr 0.1O 3 at high P O 2 , and LaIn 0.9Zr 0.1O 3+ δ shows an entirely different conduction behavior in the measured oxygen partial pressures.