Ni x Fe 3 − xO4 thin films with varying Ni amount (0 ≤ x ≤ 1.5) were deposited on MgO(001) via reactive molecular beam epitaxy. The growth process was monitored during film deposition by means of X-ray diffraction. All prepared films exhibit a well-ordered structure with complete vertical crystallinity throughout the whole film growth and flat surfaces of the final films independent of the Ni amount. An enhancement of the vertical compression in the initial growth continuously decreases up to a film thickness of 8 nm. During further growth, all films exhibit residual and constant vertical compression with lateral adaption of the final films to the substrate lattice, as observed by high energy surface X-ray diffraction experiments. Hard X-ray photoelectron spectroscopy measurements of the final films reveal increasing Fe 3 +: Fe 2 + ratios for higher Ni content and point to additional NiO agglomerations within the films exceeding the stoichiometric Ni amount of x = 1.

中文翻译：

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实时监测 MgO(001) 上应变非化学计量的 Ni x Fe 3 − x O 4 超薄膜的生长

通过反应性分子束外延在 MgO(001) 上沉积具有不同 Ni 量 (0 ≤ x ≤ 1.5) 的 Ni x Fe 3 - xO4 薄膜。在薄膜沉积过程中通过 X 射线衍射监测生长过程。所有制备的薄膜都表现出有序的结构，在整个薄膜生长过程中具有完全的垂直结晶度，最终薄膜的平坦表面与 Ni 量无关。初始生长中垂直压缩的增强不断减小，直至薄膜厚度达到 8 nm。在进一步生长过程中，所有薄膜都表现出残余和恒定的垂直压缩，最终薄膜横向适应基板晶格，如高能表面 X 射线衍射实验所观察到的。最终薄膜的硬 X 射线光电子能谱测量显示 Fe 3 + 增加：