The grain boundary transport of lanthanum gallate has been studied with various doping concentrations, and the origins of blocking on the grain boundary are compared. La_1-xSr_xGaO₃ samples (x = 0.005, 0.01, 0.05 and 0.1) have been prepared and their bulk (grain) and grain boundary resistances been experimentally measured as a function of temperature (T: 200–550 °C) and oxygen partial pressure (Po₂) using ac-impedance measurements. In addition, Hebb-Wagner polarization measurements have been conducted to investigate the electrical conductivity of minor charge carriers in the lanthanum gallates. The grain boundary resistance in the low-doped materials (x = 0.005 and 0.01) increases with increasing Po₂ while in the highly-doped materials (x = 0.05, 0.1) it hardly depended on Po₂. At lower concentrations conduction is mixed and at higher concentrations is found to be predominantly ionic conductivity. The space charge model successfully describes the mixed conduction at the grain boundary at low-doping, but does not explain the predominant ionic conductivity at high-doping. The origin of blocking at high-doping is explained by the crystallographic asymmetry of the grain boundary with respect to the bulk and/or Sr-segregation.

研究了不同掺杂浓度的没食子酸镧的晶界迁移，并比较了在晶界发生阻挡的原因。已经制备了La _1-x Sr _x GaO ₃样品（x = 0.005、0.01、0.05和0.1），并通过实验测量了它们的体积（晶粒）和晶界电阻随温度的变化（T：200–550°C）和氧分压（P o ₂）使用交流阻抗测量。此外，已经进行了Hebb-Wagner极化测量，以研究没食子酸镧中次要载流子的电导率。低掺杂材料（x = 0.005和0.01）的晶界电阻随P o _2的增加而增加，而高掺杂材料（x = 0.05，0.1）则几乎不依赖于P o ₂。在较低的浓度下，导电是混合的，在较高的浓度下，主要是离子导电性。空间电荷模型成功地描述了低掺杂时晶界处的混合传导，但没有解释高掺杂时的主要离子传导率。高掺杂时的阻挡起因是由晶界相对于本体和/或Sr-偏析的结晶学不对称性解释的。