Magnetic properties of iron-doped channels in H-Nb2O5
| Autor: | Luis Ghivelder, Osvaldo F. Schilling |
|---|---|
| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Journal of Physics: Condensed Matter. 12:2825-2832 |
| ISSN: | 1361-648X 0953-8984 |
| DOI: | 10.1088/0953-8984/12/12/321 |
| Popis: | H-Nb2 O5 (Nb28 O70 ) is a semiconductor whose structure is built of NbO6 octahedra, which share corners and edges to form blocks parallel to the basal ac plane of the structure. One unit cell contains two blocks of 3 × 4 and 3 × 5 octahedra displaced by 1/2 b -axis spacing, besides one further Nb atom located in tetrahedrally coordinated sites along channels parallel to the b axis. Such channels contain octahedral interstices which are the preferential sites for point defect segregation in this structure. The possibility of using the channels as a framework for obtaining oriented spin arrays has never been explored in the literature. To investigate which kind of magnetic interaction would arise we manufactured a sample of H-Nb2 O5 containing enough Fe to fill part of the octahedral interstices in the channels and measured the ac susceptibility response. The results were consistent with the formation of linear chains of spins, with variable coupling constants along the chains. The variable coupling can be understood as a consequence of the influence of the large number of possible arrangements of Nb and Fe atoms along the channels upon the sign and magnitude of superexchange interactions mediated by the oxygen atoms. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|