https://doi.org/10.1007/s100530050547
Magnetisation of isolated single crystalline Fe-nanoparticles measured by a ballistic Hall micro-magnetometer
1
Ørsted Laboratory, Niels Bohr Institute,
Universitetsparken 5, 2100 Copenhagen Ø, Denmark
2
Research
Institute for Materials, University of Nijmegen, 6525 Nijmegen,
The Netherlands
Received:
1
September
1998
Revised:
21
June
1999
Published online: 15 May 2000
We present here the first magnetisation measurements on
isolated single crystalline Fe-nanoparticles performed with a
ballistic Hall micro-magnetometer. The measurements have a
sensitivity of 
and thus provide us the
possibility to study the mechanisms of magnetisation reversal in a
single nanoparticle. The magnetic properties of the nanoparticles
are influenced by their crystal structure and shape, and the
presence of an oxide surface layer. They exhibit curling of the
magnetic moments, but also a novel hysteresis behaviour. The spin
configurations found for the system agree well with numerical
calculations based on a Heisenberg Hamiltonian including the
exchange and dipole interaction and surface anisotropy.
PACS: 07.55.Jg – Magnetometers for susceptibility, magnetic moment, and magnetization measurements / 36.40.Cg – Electronic and magnetic properties of clusters / 61.46.+w – Clusters, nanoparticles, and nanocrystalline materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
