micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf ·...

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micromagnetism nanomagnetism an MMM mini-lecture by Willem van Engen on October 24, 2007 0 nm μm cm

Transcript of micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf ·...

Page 1: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

micromagnetismnanomagnetism

an

MMM mini-lectureby

Willem van Engenon

October 24, 2007

0 nm μm cm

Page 2: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

doi:10.1103/PhysRev.77.725

Page 3: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

0.06 T0.06 T 0.21 T0.21 T

Page 4: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

θ

easy

axi

s

φ

H

Page 5: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

θ

easy

ax

is

H H

anti-parallelφ = θ = π

φ

H

parallelφ = θ = 0

Page 6: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

d2Ed2

=0 Hext=2K

0M sat

Page 7: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

“Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle, 2003. ISBN 0521331358

Page 8: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

superparamagnetism

Dth3=6kBT

Kln

m0

kBT

Page 9: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

single vs. multi domain

Ddo=18

0M sat2

Page 10: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

curling ...

“Micromagnetism”, Boardman, 2006. http://www.soton.ac.uk/~rpb/

Page 11: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

... or buckling

“Development of elongated particle magnets”, Luborsky, 1961. doi:10.1063/1.2000392

Page 12: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

Dth, D

nuc, D

doFe:

Co: Dth

Dnuc

Ddo

“Development of elongated particle magnets”, Luborsky, 1961. doi:10.1063/1.2000392

Page 13: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

enough theory

applications!

Page 14: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

microfluidics ...

“The origins and the future of microfluidics”, Whitesides, 2006. doi:10.1038/nature05058

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microfluidics ...ferrofluidics

+ =

~10nm

source: Technorama

Page 16: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

microfluidics ...ferrofluidic pump

“Magnetism and microfluidics”, Pamme, 2006. doi:10.1039/b513005k

Page 17: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

surfacecoating

biosensorsmagnetic bead

magnetite grains(Fe

3O

4)

polymer matrix

Page 18: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

biosensorsbiochemical binding

Magnetic field sensorCurrent wire

Silicon chipSilicon chip

Agent Anti body

Page 19: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

biosensorsbead attachment & measurement

Magnetic field sensorCurrent wire

Silicon chipSilicon chip

Page 20: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

vortex switchingsimulations

“Current induced switching of vortex polarity in magnetic nanodisks”, Sheka et al., 2007. doi:10.1063/1.2775036

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vortex switchingMFM measurements

“Electrical switching of the vortex core in a magnetic disk”, Yamada et al., 2007. doi:10.1038/nmat1867

Page 22: micromagnetism nanomagnetism - Engenwillem.engen.nl/uni/...micronanomagnetism_redist.pdf · “Micromagnetism and the Microstructure of Ferromagnetic solids”, Kronmüller and Fahnle,

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