Paulin Mariano Andrés, Garbarino Gaston, Leyva Ana Gabriela, Mezouar Mohamed, Sacanell Joaquin
Laboratorio Argentino de Haces de Neutrones, Centro Atómico Bariloche, CNEA, Av. E. Bustillo 9500, San Carlos de Bariloche, Río Negro R8402AGP, Argentina.
European Synchrotron Radiation Facility, 71 Av. des Martyrs, Grenoble 38000, France.
Nanomaterials (Basel). 2020 Mar 31;10(4):650. doi: 10.3390/nano10040650.
Ceria (CeO)-based materials are widely used in applications such as catalysis, fuel cells and oxygen sensors. Its cubic fluorite structure with a cell parameter similar to that of silicon makes it a candidate for implementation in electronic devices. This structure is stable in a wide temperature and pressure range, with a reported structural phase transition to an orthorhombic phase. In this work, we study the structure of CeO under hydrostatic pressures up to 110 GPa simultaneously for the nanometer- and micrometer-sized powders as well as for a single crystal, using He as the pressure-transmitting medium. The first-order transition is clearly present for the micrometer-sized and single-crystal samples, while, for the nanometer grain size powder, it is suppressed up to at least 110 GPa. We show that the stacking fault density increases by two orders of magnitude in the studied pressure range and could act as an internal constraint, avoiding the nucleation of the high-pressure phase.
基于二氧化铈（CeO）的材料广泛应用于催化、燃料电池和氧传感器等领域。其立方萤石结构的晶胞参数与硅相似，这使其成为电子器件应用的候选材料。这种结构在很宽的温度和压力范围内都很稳定，据报道会发生向正交相的结构相变。在这项工作中，我们以氦气作为压力传递介质，同时研究了高达110吉帕静水压力下纳米级和微米级粉末以及单晶的CeO结构。微米级和单晶样品中明显存在一级相变，而对于纳米粒度粉末，至少在110吉帕压力下该相变受到抑制。我们表明，在所研究的压力范围内，堆垛层错密度增加了两个数量级，并且可能作为一种内部约束，避免高压相的形核。
