Interfacially engineered oxygen octahedral rotations and their impact on strain relief in coherently grown SrRuO3 films
Interfacially engineered oxygen octahedral rotations and their impact on strain relief in coherently grown SrRuO3 films
复制标题
DOI：
10.1103/physrevb.94.024112
复制
发表时间：
2016-07-15
影响因子：
3.7
通讯作者：
Shimakawa, Yuichi
中科院分区：
文献类型：
--
作者：
Kan, Daisuke;Wakabayashi, Yusuke;Shimakawa, Yuichi
我们报告了界面工程氧八面体旋转的同步加速器 X 射线衍射研究及其对钙钛矿 SrRuO3 薄膜应变消除的影响。我们表明，具有不同模式和大小的八面体旋转可以适应相干生长的薄膜。直接生长在 GdScO3 基底上的 SrRuO3 薄膜具有 RuO6 八面体旋转，在 Glazer 符号中具有 a(-)b(+)c(-) 图案，旋转角度为 alpha(rot) = 6.6 +/- 0.2 度，beta(rot) = 5.5 +/- 0.2 度，gamma(rot) = 3.6 +/- 0.2 度。另一方面，当在 SrRuO3 和 GdScO3 之间插入没有 TiO6 旋转的 1 nm 厚的 BaTiO3 层时，SrRuO3 具有 a(-)b(0)c(+) 的 RuO6 旋转，并且 alpha(rot) = 5.6 +/- 0.8 度和 gamma(rot) = 3.6 +/- 0.8 度。这些结果表明，根据界面结构，SrRuO3 中容纳的八面体旋转存在一定的自由度，并且当绕 [010](pc) 轴的旋转受阻时，γ(rot) 旋转在薄膜的结构特性中发挥着重要作用。我们还发现薄膜中的应变消除受到界面工程八面体旋转的影响。界面 BaTiO3 层导致 t-SRO 薄膜中的面内周期性晶格调制，从而可以缓解基板引起的应变的各向异性。结果强调了界面结构作为一个因素的重要性，它不仅决定了相干生长的 SRO 薄膜中的八面体旋转，还决定了其中的应变消除。
We report synchrotron x-ray diffraction investigations of interfacially engineered oxygen octahedral rotations and their impact on strain relief in perovskite SrRuO3 films. We show that octahedral rotations with distinct patterns and magnitudes can be accommodated into coherently grown films. The SrRuO3 film grown directly on the GdScO3 substrate has the RuO6 octahedral rotation with the a(-)b(+)c(-) pattern in the Glazer notation and the rotation angles of alpha(rot) = 6.6 +/- 0.2 degrees, beta(rot) = 5.5 +/- 0.2 degrees, and gamma(rot) = 3.6 +/- 0.2 degrees. On the other hand, when a 1-nm-thick BaTiO3 layer without TiO6 rotations is inserted between the SrRuO3 and GdScO3, the SrRuO3 has the RuO6 rotation with a(-)b(0)c(+), and alpha(rot) = 5.6 +/- 0.8 degrees and gamma(rot) = 3.6 +/- 0.8 degrees. These results indicate that there are some degrees of freedom in the octahedral rotations accommodated in SrRuO3 depending on the interface structure and that the gamma(rot) rotations play the important roles in the film's structural properties when the rotation about the [010](pc) axis is blocked. We also found that the strain relief in the film is influenced by the interfacially engineered octahedral rotations. The interfacial BaTiO3 layer results in the in-plane periodic lattice modulation in the t-SRO film, allowing for the anisotropic relief of the substrate-induced strain. The results highlight the importance of the interface structure as a factor, determining not only octahedral rotations in coherently grown SRO films but also the strain reliefs in them.