Influences of hydration-dehydration on local structure in layered perovskite LaSrFeO

層状ペロブスカイトLaSrFeOの水和-脱水反応に伴う局所構造変化

八木 祐太朗*; 脇田 雄大*; 籠宮 功*; 松江 郁弥*; 柿本 健一*; 松村 大樹   ; 米田 安宏   

Yagi, Yutaro*; Wakita, Yudai*; Kagomiya, Isao*; Matsue, Ikuya*; Kakimoto, Kenichi*; Matsumura, Daiju; Yoneda, Yasuhiro

The layered perovskite LaSrFeO (LSF) easily hydrates under ambient air. The hydrated LSF transports hydroxides in the middle-temperature range of 100 C - 250 C. This study used X-ray absorption fine structure analysis on normal and hydrated LSF from room temperature to 350 C to evaluate the relationship between local structures and ion transport characteristics. The HO molecules are mainly intercalated into rock-salt interlayers, which are close to the La1 and O3 sites. The generated OH ions are found at O3 sites, which are closer to Sr ions than La ions. The intercalated HO molecules and formed OH ions expand the spaces of the rock-salt interlayers. The temperature dependence of the local crystal structure was also studied in this study. According to the findings, the presence of OH ions on the O3 sites, which are closer to Sr ions, plays a significant role in OH transport in the medium temperature range.