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Magnetic properties of silica coated spindle-type hematite particles

Reufer, M.; Dietsch, H.; Gasser, U.; Grobety, B.; Hirt, A. M.; Malik, V. K. and Schurtenberger, Peter LU (2011) In Journal of Physics: Condensed Matter 23(6).
Abstract
Magnetic properties of particles are generally determined from randomly oriented ensembles and the influence of the particle orientation on the magnetic response is neglected. Here, we report on the magnetic characterization of anisotropic spindle-type hematite particles. The easy axis of magnetization is within the basal plane of hematite, which is oriented perpendicular to the spindle axis. Two standard synthesis routes are compared and the effects of silica coating and particle orientation on the magnetic properties are investigated. Depending on the synthesis route we find fundamentally different magnetic behavior compatible with either single domain particles or superparamagnetic sub-units. Furthermore, we show that silica coating... (More)
Magnetic properties of particles are generally determined from randomly oriented ensembles and the influence of the particle orientation on the magnetic response is neglected. Here, we report on the magnetic characterization of anisotropic spindle-type hematite particles. The easy axis of magnetization is within the basal plane of hematite, which is oriented perpendicular to the spindle axis. Two standard synthesis routes are compared and the effects of silica coating and particle orientation on the magnetic properties are investigated. Depending on the synthesis route we find fundamentally different magnetic behavior compatible with either single domain particles or superparamagnetic sub-units. Furthermore, we show that silica coating reduces the mean blocking temperature to nearly room temperature. The mechanical stress induced by the silica coating appears to reduce the magnetic coupling between the sub-units. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physics: Condensed Matter
volume
23
issue
6
publisher
IOP Publishing
external identifiers
  • wos:000286624000002
  • scopus:79551680096
ISSN
1361-648X
DOI
10.1088/0953-8984/23/6/065102
language
English
LU publication?
yes
id
938878b7-1eca-454d-b77c-1aa1fa176791 (old id 1882449)
date added to LUP
2011-04-06 14:09:33
date last changed
2017-10-22 04:17:06
@article{938878b7-1eca-454d-b77c-1aa1fa176791,
  abstract     = {Magnetic properties of particles are generally determined from randomly oriented ensembles and the influence of the particle orientation on the magnetic response is neglected. Here, we report on the magnetic characterization of anisotropic spindle-type hematite particles. The easy axis of magnetization is within the basal plane of hematite, which is oriented perpendicular to the spindle axis. Two standard synthesis routes are compared and the effects of silica coating and particle orientation on the magnetic properties are investigated. Depending on the synthesis route we find fundamentally different magnetic behavior compatible with either single domain particles or superparamagnetic sub-units. Furthermore, we show that silica coating reduces the mean blocking temperature to nearly room temperature. The mechanical stress induced by the silica coating appears to reduce the magnetic coupling between the sub-units.},
  author       = {Reufer, M. and Dietsch, H. and Gasser, U. and Grobety, B. and Hirt, A. M. and Malik, V. K. and Schurtenberger, Peter},
  issn         = {1361-648X},
  language     = {eng},
  number       = {6},
  publisher    = {IOP Publishing},
  series       = {Journal of Physics: Condensed Matter},
  title        = {Magnetic properties of silica coated spindle-type hematite particles},
  url          = {http://dx.doi.org/10.1088/0953-8984/23/6/065102},
  volume       = {23},
  year         = {2011},
}