The electron beam, during high-resolution transmission electron microscopy, was employed to induce a phase transition in La0.6Sr0.4CoO2.5 (LSC) from a brownmillerite ordering to an oxygen deficient perovskite structure. Prior to irradiation, a strongly alternating out-of-plane lattice parameter was observed, reflecting electrostatic interactions between AO and BO/BO2 planes in the brownmillerite ordering. During electron beam irradiation for one hour, the oxygen vacancy ordering vanished gradually, and a uniform cubic perovskite structure prevailed. To exclude beam-induced heating effects, in situ heating experiments were performed, revealing a stable brownmillerite ordering in the relevant temperature range (up to at least 500 °C). Thus, we conclude that the phase transition is caused by knock-on processes that affect oxygen vacancies in terms of a transition from structural vacancies toward extremely high concentrations of randomly distributed point defects in the ABO3 structure.

中文翻译：

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La0.6Sr0.4CoO3− δ 中电子束诱导的褐钙钛矿-钙钛矿相变

在高分辨率透射电子显微镜下，电子束被用来诱导 La0.6Sr0.4CoO2.5 (LSC) 从有序的褐钙钛矿到缺氧钙钛矿结构的相变。在辐照之前，观察到强烈交替的面外晶格参数，反映了褐铝石有序中 AO 和 BO/BO2 平面之间的静电相互作用。在电子束照射 1 小时的过程中，氧空位有序逐渐消失，出现均匀的立方钙钛矿结构。为了排除光束引起的加热效应，进行了原位加热实验，揭示了在相关温度范围内（至少 500 °C）稳定的褐铁矿有序排列。因此，