Size-dependent properties of magnetic iron oxidenanocrystals
| Autor: | Arnaud Demortière, Pierre Panissod, Benoit P. Pichon, Geneviève Pourroy, Bertrand Donnio, Sylvie Begin-Colin, Daniel Guillon |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Materials science
Thermal decomposition Aucun Iron oxide Metal Nanoparticles Nanoparticle Maghemite engineering.material Ferrosoferric Oxide Magnetics chemistry.chemical_compound Nuclear magnetic resonance X-Ray Diffraction Nanocrystal chemistry Chemical physics engineering General Materials Science Nanometre Particle Size Anisotropy Magnetite |
| Zdroj: | Nanoscale. 3:225-232 |
| ISSN: | 2040-3372 2040-3364 |
| Popis: | The fine control of iron oxide nanocrystal sizes within the nanometre scale (diameters range from 2.5 to 14 nm) allows us to investigate accurately the size-dependence of their structural and magnetic properties. A study of the growth conditions of these nanocrystals obtained by thermal decomposition of an iron oleate precursor in high-boiling point solvents has been carried out. Both the type of solvent used and the ligand/precursor ratio have been systematically varied, and were found to be the key parameters to control the growth process. The lattice parameters of all the nanocrystals deduced from X-ray diffraction measurements are consistent with a structure of the type Fe(3-x)O(4), i.e. intermediate between magnetite and maghemite, which evolves toward the maghemite structure for the smallest sizes (x = 1/3). The evolution of the magnetic behavior with nanoparticle sizes emphasizes clearly the influence of the surface, especially on the saturation magnetization M(s) and the magneto-crystalline anisotropy K. Dipolar interactions and thermal dependence have been also taken into account in the study on the nanoscale size-effect of magnetic properties. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|