micromagnetism nanomagnetism an MMM mini-lecture by Willem van Engen on October 24, 2007 0 nm μm cm
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micromagnetismnanomagnetism
an
MMM mini-lectureby
Willem van Engenon
October 24, 2007
0 nm μm cm
0.06 T0.06 T 0.21 T0.21 T
θ
easy
axi
s
φ
H
θ
easy
ax
is
H H
anti-parallelφ = θ = π
φ
H
parallelφ = θ = 0
d2Ed2
=0 Hext=2K
0M sat
“Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle, 2003. ISBN 0521331358
superparamagnetism
Dth3=6kBT
Kln
m0
kBT
single vs. multi domain
Ddo=18
0M sat2
curling ...
“Micromagnetism”, Boardman, 2006. http://www.soton.ac.uk/~rpb/
... or buckling
“Development of elongated particle magnets”, Luborsky, 1961. doi:10.1063/1.2000392
Dth, D
nuc, D
doFe:
Co: Dth
Dnuc
Ddo
“Development of elongated particle magnets”, Luborsky, 1961. doi:10.1063/1.2000392
enough theory
applications!
microfluidics ...
“The origins and the future of microfluidics”, Whitesides, 2006. doi:10.1038/nature05058
microfluidics ...ferrofluidic pump
“Magnetism and microfluidics”, Pamme, 2006. doi:10.1039/b513005k
surfacecoating
biosensorsmagnetic bead
magnetite grains(Fe
3O
4)
polymer matrix
biosensorsbiochemical binding
Magnetic field sensorCurrent wire
Silicon chipSilicon chip
Agent Anti body
biosensorsbead attachment & measurement
Magnetic field sensorCurrent wire
Silicon chipSilicon chip
vortex switchingsimulations
“Current induced switching of vortex polarity in magnetic nanodisks”, Sheka et al., 2007. doi:10.1063/1.2775036
vortex switchingMFM measurements
“Electrical switching of the vortex core in a magnetic disk”, Yamada et al., 2007. doi:10.1038/nmat1867
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