micromagnetism nanomagnetism an MMM mini-lecture by Willem van - - PowerPoint PPT Presentation

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micromagnetism nanomagnetism an MMM mini-lecture by Willem van Engen on October 24, 2007 0 nm m cm doi:10.1103/PhysRev.77.725 0.06 T 0.21 T 0.21 T 0.06 T easy axis H easy axis anti-parallel parallel = =

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SLIDE 1

micromagnetism nanomagnetism

an

MMM mini-lecture

by

Willem van Engen

  • n

October 24, 2007

nm μm cm

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SLIDE 2

doi:10.1103/PhysRev.77.725

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SLIDE 3

0.06 T 0.06 T 0.21 T 0.21 T

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SLIDE 4

θ

easy axis

φ H

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SLIDE 5

θ

easy axis

H H

anti-parallel

φ = θ = π φ H

parallel

φ = θ = 0

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SLIDE 6

d

2 E

d

2 =0  Hext=

2K 0 M sat

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SLIDE 7

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

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SLIDE 8

superparamagnetism

Dth

3=6kBT

 K ln m 0

kBT

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SLIDE 9

single vs. multi domain

Ddo= 18 0 M sat

2

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SLIDE 10

curling ...

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

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SLIDE 11

... or buckling

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

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SLIDE 12

Dth, Dnuc, Ddo Fe: Co: Dth Dnuc Ddo

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

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SLIDE 13

enough theory applications!

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SLIDE 14

microfluidics ...

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

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microfluidics ... ferrofluidics

+ =

~10nm

source: Technorama

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SLIDE 16

microfluidics ... ferrofluidic pump

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

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SLIDE 17

surface coating

biosensors magnetic bead

magnetite grains (Fe3O4) polymer matrix

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SLIDE 18

biosensors biochemical binding

Magnetic field sensor Current wire

Silicon chip

Silicon chip Agent Anti body

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SLIDE 19

biosensors bead attachment & measurement

Magnetic field sensor Current wire

Silicon chip

Silicon chip

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SLIDE 20

vortex switching simulations

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

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vortex switching MFM measurements

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

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SLIDE 22
  • the end -