In-situ STM and XRD studies on Nb-H films: Coherent and incoherent phase transitions
In-situ STM and XRD studies on Nb-H films: Coherent and incoherent phase transitions
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DOI：
10.1016/j.jallcom.2014.12.103
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发表时间：
2015-10-05
影响因子：
6.2
通讯作者：
Pundt, Astrid
中科院分区：
文献类型：
--
作者：
Burlaka, Vladimir;Wagner, Stefan;Pundt, Astrid
通过扫描隧道显微镜 (STM) 并辅以 X 射线衍射 (XRD) 测量，研究了 25 nm 和 40 nm 外延 Nb 膜中的氢化物沉淀。结合起来，这些方法可产生有关 293 K 时的相变、共格状态、氢化物沉淀物的密度和尺寸以及横向分布的信息。对于两种膜厚度，均使用 STM 检测氢化物的形成； XRD 很容易漏掉它。虽然 25 nm 薄膜表现出相干相变，但 40 nm 薄膜的相变却是不相干的。这与理论非常吻合。研究发现相变特征强烈依赖于相干态：大量小氢化物出现在相干态中，而少量大氢化物则在非相干态中演化。 (C) 2014 Elsevier B.V. 保留所有权利。
Hydride precipitation in 25 nm and 40 nm epitaxial Nb-films was studied by Scanning Tunnelling Microscopy (STM) supported by X-ray diffraction (XRD) measurements. In combination, these methods yield information about the phase transition, the coherency state, the hydride precipitates' density and size as well as their lateral distribution, at 293 K. For both film thicknesses, hydride formation was detected with STM; it can be easily missed by XRD. While the 25 nm film showed a coherent phase transition, the phase transition was incoherent for the 40 nm film. This is in good accordance with theory. The phase transition features are found to strongly depend on the coherency state: a large number of small hydrides appear in the coherent regime while a small number of large hydrides evolve in the incoherent regime. (C) 2014 Elsevier B.V. All rights reserved.