| Автор | Masashige Onoda |
| Автор | Takeo Kagami |
| Дата выпуска | 1999-05-03 |
| dc.description | The structural and electronic properties of the Ca<sub>1-x</sub>Na<sub>x</sub>V<sub>2</sub>O<sub>5</sub> system, where the composition CaV<sub>2</sub>O<sub>5</sub> exhibits an isolated dimer-like spin-gap state, and NaV<sub>2</sub>O<sub>5</sub> indicates a linear-chain magnetic behaviour and undergoes a spin-singlet transition at T<sub>c</sub> = 34 K, have been explored by means of x-ray four-circle diffraction and through magnetization and electron paramagnetic resonance measurements. The crystal structures with 0<x0.1 and 0.8 x1 are isomorphous with that of CaV<sub>2</sub>O<sub>5</sub>, where the space group is Pmmn. The effective V valence is correlated with the V-O bond length in the VO<sub>5</sub> pyramid, and the transfer integral for the next-nearest-neighbour V-V path is suggested to be larger than those for other paths, which may be consistent with the formation mechanisms of the dimer in the Ca-rich compounds and the V-O-V molecular orbital in the Na-rich compounds. The magnetic properties for 0<x0.1 are interpreted as being governed by contributions from the dimer which is formed between the V zigzag chains and from the isolated spins that are present due to the breaking of the dimer. On the other hand, the properties for 0.9 x<1 still exhibit linear-chain behaviours, and for x0.97 the singlet transition with a large reduction of the exchange coupling constant disappears, and no magnetic ordering takes place. The characteristic spin dynamics for the Na-rich compounds is also discussed |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Crystal structures and electronic properties in the crossover region between the spin-gap system CaV<sub>2</sub>O<sub>5</sub> and the linear-chain system NaV<sub>2</sub>O<sub>5</sub> |
| Тип | paper |
| DOI | 10.1088/0953-8984/11/17/321 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 11 |
| Первая страница | 3475 |
| Последняя страница | 3488 |
| Аффилиация | Masashige Onoda; Institute of Physics, University of Tsukuba, Tennodai, Tsukuba 305-8571, Japan |
| Аффилиация | Takeo Kagami; Institute of Physics, University of Tsukuba, Tennodai, Tsukuba 305-8571, Japan |
| Выпуск | 17 |
