Residual attractive force between superparamagnetic nanoparticles
| dc.creator | Dobson, John F. | |
| dc.creator | Gray, Evan MacA. | |
| dc.date | 2009-02-20 | |
| dc.date.accessioned | 2026-07-07T12:45:25Z | |
| dc.date.available | 2026-07-07T12:45:25Z | |
| dc.description | A superparamagnetic nanoparticle (SPN) is a nanometre-sized piece of a material that would, in bulk, be a permanent magnet. In the SPN the individual atomic spins are aligned via Pauli effects into a single giant moment that has easy orientations set by shape or magnetocrystalline anisotropy. Above a size-dependent blocking temperature $T_{b}(V,τ_{obs})$, thermal fluctuations destroy the average moment by flipping the giant spin between easy orientations at a rate that is rapid on the scale of the observation time $τ_{obs}$. We show that, depite the vanising of the average moment, two SPNs experience a net attractive force of magnetic origin, analogous to the van der Waals force between molecules that lack a permanent electric dipole. This could be relevant for ferrofluids, for the clumping of SPNs used for drug delivery, and for ultra-dense magnetic recording media. | |
| dc.description | 21 pp | |
| dc.identifier | https://arxiv.org/abs/0902.3684 | |
| dc.identifier | http://arxiv.org/abs/0902.3684 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/221078 | |
| dc.subject | Other Condensed Matter | |
| dc.title | Residual attractive force between superparamagnetic nanoparticles | |
| dc.type | text |