Influences of Hydration-Dehydration on Local Structure in Layered Perovskite LaSr3Fe3O10

The layered perovskite LaSr3Fe3O10 (LSF) easily hydrates under ambient air. The hydrated LSF transports hydroxides in the middle-temperature range of 100 degrees C-250 degrees C. This study used X-ray absorption fine structure analysis on normal and hydrated LSF from room temperature to 350 degrees C to evaluate the relationship between local structures and ion transport characteristics. The H2O 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 H2O 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.