Electroresistance (ER) has been intensively studied in low- and intermediate-bandwidth manganites, which possess phase separation characteristics. As for the Sr- and Ba-doped large-bandwidth manganites, however, few results about ER have been reported so far. Here we report ER effect in oxygen-deficient La0.8Ba0.2MnO3-δ thin films, which were obtained by applying a large electric current (33 mA) to the pristine films in vacuum. While the pristine film displays a negligible change in resistivity with respect to the test current, the oxygen-deficient film shows significant ER effect, i.e. ER ratio of -22% at 260 K under a test current of 0.3 mA. By gradually restoring oxygen content in the films, it is found that the ER effect is closely related to the residual resistivity at low temperatures, demonstrating the key role of grain boundaries. Furthermore, the residual resistivity can readily be tuned by heating the oxygen-deficient films in air, suggesting strong oxygen activity in the grain boundaries. The magnetoresistance (MR) data show current dependent feature, also revealing the role of grain boundaries. At 40 K, the MR ratio of the 100 °C restored film under 30 kOe increases from -15% to -25% when decreasing the test current from 1 to 10-3 mA. The large ER effect in the oxygen-deficient films is discussed based upon the conductive filament picture in grain boundaries. Our approach to controlling the ER effect through oxygen deficiency makes oxide films more promising for potential applications in the memristive devices and neuomorphic computing.

中文翻译：

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缺氧La0.8Ba0.2MnO3−δ薄膜中的电阻效应


具有相分离特性的中低带宽锰酸盐的电阻（ER）已得到深入研究。然而，对于Sr和Ba掺杂的大带宽锰酸盐，迄今为止关于ER的报道还很少。在这里，我们报告了缺氧 La0.8Ba0.2MnO3-δ 薄膜中的电流变效应，该效应是通过在真空中对原始薄膜施加大电流（33 mA）而获得的。虽然原始薄膜的电阻率相对于测试电流的变化可以忽略不计，但缺氧薄膜却表现出显着的ER效应，即在0.3mA的测试电流下在260K下的ER比率为-22%。通过逐渐恢复薄膜中的氧含量，发现ER效应与低温下的残余电阻率密切相关，证明了晶界的关键作用。此外，通过在空气中加热缺氧薄膜可以很容易地调节残余电阻率，这表明晶界中存在很强的氧活性。磁阻 (MR) 数据显示了电流相关特征，也揭示了晶界的作用。在 40 K 时，当测试电流从 1 mA 降低到 10-3 mA 时，100 °C 恢复膜在 30 kOe 下的 MR 比从 -15% 增加到 -25%。基于晶界中的导电丝图像讨论了缺氧薄膜中的大电流变效应。我们通过缺氧来控制ER效应的方法使得氧化物薄膜在忆阻器件和新拟态计算中的潜在应用更具前景。