DEN/Service de Recherches Metallurgiques Appliquees, CEA, Universite Paris-Saclay, F-91191, Centralesupelec/SPMS/UMR-8085/LRC CARMEN, 92292, Chatenay Malabry, France.
ANSTO, Lucas Heights, NSW, Australia.
Sci Rep. 2017 Jun 16;7(1):3727. doi: 10.1038/s41598-017-02787-w.
Intuitively scientists accept that order can emerge from disorder and a significant amount of effort has been devoted over many years to demonstrate this. In metallic alloys and oxides, disorder at the atomic scale is the result of occupation at equivalent atomic positions by different atoms which leads to the material exhibiting a fully random or modulated scattering pattern. This arrangement has a substantial influence on the material's properties, for example ionic conductivity. However it is generally accepted that oxides, such as defect fluorite as used for nuclear waste immobilization matrices and fuel cells, are the result of disorder at the atomic scale. To investigate how order at the atomic scale induces disorder at a larger scale length, we have applied different techniques to study the atomic composition of a homogeneous La Zr O pyrochlore, a textbook example of such a structure. Here we demonstrate that a pyrochlore, which is considered to be defect fluorite, is the result of intricate disorder due to a random distribution of fully ordered nano-domains. Our investigation provides new insight into the order disorder transformations in complex materials with regards to domain formation, resulting in a concord of chemistry with crystallography illustrating that order can induce disorder.
直觉上，科学家们接受无序中可以产生有序，并且多年来已经投入了大量精力来证明这一点。在金属合金和氧化物中，原子尺度上的无序是由不同原子占据等效原子位置导致的，这导致材料表现出完全随机或调制的散射模式。这种排列对材料的性质有很大的影响，例如离子导电性。然而，人们普遍认为，氧化物，如用于核废料固化基质和燃料电池的缺陷萤石，是原子尺度上无序的结果。为了研究原子尺度上的有序如何在较大的尺度长度上诱导无序，我们应用了不同的技术来研究一种均匀的 LaZrO 钙钛矿的原子组成，这是这种结构的一个典型例子。在这里，我们证明了钙钛矿，被认为是缺陷萤石，是由于完全有序的纳米域随机分布而导致的复杂无序的结果。我们的研究为复杂材料的有序-无序转变提供了新的见解，涉及到畴的形成，导致化学与晶体学的一致性，表明有序可以诱导无序。
