A doping strategy aimed at improving n-type conductivity in perovskite oxides by enhancing bulk oxide ion mobility is proposed and discussed. To justify and further assess this premise, the oxygen deficiency (δ) and conductivity (σ) of reduced La_(0.4)Sr_(0.4)Ga_xTi_(1-x)O_(3-x/2-δ) (0 ≤ x ≤ 0.15) samples were studied as a function of Ga doping (x). Both δ and σ were found to increase significantly with Ga doping. After a typical reduction process carried out at 1000 °C in 5H2/Ar the samples showed an increase in δ from 0.035 to 0.060 with doping. The corresponding conductivity also increased with doping showing a maximum of ～50 S cm~(-1) (measured at 880 °C in 5 H2/Ar on ～62 dense pellet) for x = 0.05. Conductivity data suggests Ga doping promotes fast reduction and significandy improves the stability of the reduced phase in oxidizing conditions. Although the studied compositions preserved their cubic crystal structure throughout testing and showed no sign of degradation of the microstructure, some Ga loss was shown to take place at low pO2. However, after a first redox cycle, no further change in Ga stoichiometry was observed. Two mechanisms that account for the manner in which Ga is lost from the perovskite lattice are proposed and discussed.
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机译：提出并讨论了一种旨在通过提高本体氧化物离子淌度来提高钙钛矿氧化物中n型电导率的掺杂策略。为了证明和进一步评估这一前提，研究了降低La_（0.4）Sr_（0.4）Ga_xTi_（1-x）O_（3-x/2-δ）（0 ≤ x ≤ 0.15）样品的缺氧率（δ）和电导率（σ）作为Ga掺杂（x）的函数。发现 δ 和 σ 都随着 Ga 掺杂而显着增加。在1000°C下以5%H2/Ar进行典型的还原过程后，样品的掺杂δ从0.035增加到0.060。相应的电导率也随着掺杂的增加而增加，当x = 0.05时，最大值为~50 S cm~（-1）（在880 °C下，在5% H2/Ar和~62%致密颗粒中测量）。电导率数据表明，Ga掺杂促进了快速还原，并显著提高了还原相在氧化条件下的稳定性。尽管所研究的组合物在整个测试过程中保持了其立方晶体结构，并且没有显示出微观结构降解的迹象，但在低 pO2 下会发生一些 Ga 损失。然而，在第一个氧化还原循环之后，没有观察到 Ga 化学计量的进一步变化。提出并讨论了两种解释Ga从钙钛矿晶格中丢失的机制。
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