| Автор | S Hull |
| Автор | P Berastegui |
| Дата выпуска | 1999-07-12 |
| dc.description | The ionic conductivity and crystal structure of PbF<sub>2</sub> doped with high concentrations of KF, RbF and CsF have been investigated at elevated temperatures using complex-impedance spectroscopy and powder neutron diffraction. In the case of (PbF<sub>2</sub>)<sub>1-x</sub>-(KF)<sub>x</sub>, a high-temperature superionic phase with a body-centred-cubic cation sublattice is observed for 0.333 x0.68, in which the anions predominantly occupy the tetrahedral interstices. The corresponding phase in the (PbF<sub>2</sub>)<sub>1-x</sub>(RbF)<sub>x</sub> system is observed for 0.333 x0.500, though there is a gradual tendency towards cation ordering over the 0,0,0 and 1/2,1/2,1/2 sites as x increases. This process is accompanied by a change in the preferred anion sites in favour of a subset of the octahedral cavities, such that the mean structure tends towards a partially ordered perovskite-type arrangement. In the (PbF<sub>2</sub>)<sub>1-x</sub>-(CsF)<sub>x</sub> system only a single phase at a composition x = 0.500 is observed. This phase adopts a fully ordered perovskite structure and shows no evidence of superionic behaviour up to its melting point. The structural behaviour of the three (PbF<sub>2</sub>)<sub>1-x</sub>(MF)<sub>x</sub> systems with M = K<sup>+</sup>, Rb<sup>+</sup> and Cs<sup>+</sup> is discussed in relation to the changes in the measured ionic conductivity with temperature and dopant concentration. The implications of these results for the wider question of possible superionic behaviour within halide perovskites is also discussed. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Superionic phases in the (PbF<sub>2</sub>)<sub>1-x</sub>-(MF)<sub>x</sub>, M = K, Rb and Cs, systems |
| Тип | paper |
| DOI | 10.1088/0953-8984/11/27/303 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 11 |
| Первая страница | 5257 |
| Последняя страница | 5272 |
| Аффилиация | S Hull; The ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK |
| Аффилиация | P Berastegui; The ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK |
| Выпуск | 27 |
