Krypton ion irradiation was carried out on Fe₃O₄ epitaxial thin films grown on MgO $(001)$ substrates. The spinel structure $(Fd\overline{3}m)$ of Fe₃O₄ was found to be transformed into another structure as a result of the ion irradiation without any loss of the epitaxial relationship with the MgO substrate. Both total film thickness and, therefore, the composition ratio between Fe and O remained the same even after the ion irradiation process, as confirmed by both cross-sectional transmission electron microscope images and Rutherford backscattering analysis. An x-ray diffraction experiment revealed that the irradiated crystal possessed a rocksalt structure $(Fm\overline{3}m)$, with the lattice constant being approximately half of that of Fe₃O₄. Ion irradiation, thus, gave rise to a topotactic crystal transformation to wüstite with a composition of Fe_0.75O, which is a metastable phase of iron oxides.

中文翻译：

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Kr离子辐照外延Fe3O4薄膜的尖晶石晶体结构从尖晶石铁素体转变为钨铁石。

在MgO上生长的Fe ₃ O ₄外延薄膜上进行离子辐照$（00\mathrm{1个}）$基材。尖晶石结构$（Fd\overline{3}米）$通过离子辐照，发现Fe ₃ O _4中的Fe ₃ O ₄转变为另一种结构，而与MgO衬底的外延关系没有任何损失。截面透射电子显微镜图像和卢瑟福背散射分析均证实，即使在离子辐照后，总膜厚以及Fe和O之间的组成比仍保持不变。X射线衍射实验表明，被辐照的晶体具有岩盐结构。$（F米\overline{3}米）$的晶格常数约为Fe ₃ O _4的一半。因此，离子辐射引起组成为Fe _0.75 O的铁素体的全同立构晶体转变为白铁矿，这是铁氧化物的亚稳定相。