| Автор | Turquat, C. |
| Автор | Muller, C. |
| Автор | Nigrelli, E. |
| Автор | Leroux, C. |
| Автор | Soubeyroux, J.-L. |
| Автор | Nihoul, G. |
| Дата выпуска | 2000 |
| dc.description | HfV<sub>2</sub>O<sub>7</sub> powders were prepared by means of thermal decomposition of a mixture of vanadyl and hafnyl oxalates in air at 973 K. The room temperature structure and its evolution with temperature was investigated using both electron microscopy (TEM and HREM) and powder diffraction (X-ray and neutron) techniques combined with DSC measurements. HfV<sub>2</sub>O<sub>7</sub> exhibits two temperature-induced phase transitions between room temperature and 480 K. Over the highest transition (370 K), HfV<sub>2</sub>O<sub>7</sub> crystallizes in a cubic system with a cell parameter of 8.75 Å and $Pa\bar{3}$ space group. A negative thermal expansion is observed in this high temperature phase and can be correlated to anisotropic oxygen atom displacements. On the other hand, the room temperature structure of HfV<sub>2</sub>O<sub>7</sub> is also described in a cubic symmetry, but the existence of superstructure reflections leads to a cell parameter three times larger than for the high temperature structure (~ 26.25 Å). Moreover, HREM calculations have shown that the atomic positions, usually used to describe the superstructures of the ZrV<sub>2</sub>O<sub>7</sub> compounds, cannot be used in the case of HfV<sub>2</sub>O<sub>7</sub> at room temperature. |
| Формат | application.pdf |
| Издатель | EDP Sciences |
| Копирайт | © EDP Sciences, 2000 |
| Название | Structural investigation of temperature-induced phase transitions in HfV<sub>2</sub>O<sub>7</sub> |
| Тип | research-article |
| DOI | 10.1051/epjap:2000115 |
| Electronic ISSN | 1286-0050 |
| Print ISSN | 1286-0042 |
| Журнал | The European Physical Journal Applied Physics |
| Том | 10 |
| Первая страница | 15 |
| Последняя страница | 27 |
| Аффилиация | Turquat C.; Laboratoire Matériaux Multiphasés Interfaces, Université de Toulon et du Var, B.P. 132, 83957 La Garde Cedex, France |
| Аффилиация | Muller C.; Laboratoire Matériaux Multiphasés Interfaces, Université de Toulon et du Var, B.P. 132, 83957 La Garde Cedex, France |
| Аффилиация | Nigrelli E.; Laboratoire Matériaux Multiphasés Interfaces, Université de Toulon et du Var, B.P. 132, 83957 La Garde Cedex, France |
| Аффилиация | Leroux C.; Laboratoire Matériaux Multiphasés Interfaces, Université de Toulon et du Var, B.P. 132, 83957 La Garde Cedex, France |
| Аффилиация | Soubeyroux J.-L.; Laboratoire de Cristallographie, CNRS, B.P. 166, 38042 Grenoble Cedex 09, France |
| Аффилиация | Nihoul G.; Laboratoire Matériaux Multiphasés Interfaces, Université de Toulon et du Var, B.P. 132, 83957 La Garde Cedex, France |
| Выпуск | 1 |
