http://en.wikipedia.org/wiki/Giant_magnetoresistance

http://en.wikipedia.org/wiki/Giant_magnetoresistance

http://en.wikipedia.org/wiki/Giant_magnetoresistance#mediaviewer/File:GMR.svg
RKKY in multilayers
MR as fct of spacer thickness
Wang et al. EPL 87 47001 (2009)
Parkin et al. Phys. Rev. B 44, 7131(R) (1991)
Parkin et al. Phys. Rev. Lett. 64, 2304 (1990)
RKKY multilayers (theory)
TMR
http://de.wikipedia.org/w/index.php?title=Datei:TunnelSchema_TMR.png&filetimestamp=20090503090921
Barrier height f
EF
eV
Metal 1
t
Metal 2
Barrier thickness
I12 (E)  N1 (E-eV) N2 (E) T2 x f(E-eV) [1-f(E)] , T2 exp (-ctf)
I21 (E)  N1 (E-eV) N2 (E) T2 x [1- f(E-eV)] f (E)
Integration and small voltages only yield:
I  DOS1 DOS2 (E) x ∫ [f(E-eV)- f (E)]dE, for low T ∫ =eV
 I/V  DOS1 (EF) DOS2 (EF)
http://www.pha.jhu.edu/~wgwang/pics/DMTJ%20TEM.jpg
Inomata et al. Appl. Phys. Lett. 86, 232503 (2005);
http://www.jst.go.jp/sicp/ws2009_sp1st/presentation/15.pdf
Courtesy S. Yuasa (AIST)
Coherent tunneling – band filtering
TMR in Co2MnaSig Heusler films
Liu et al. Appl. Phys. Lett. 101, 132418 (2012);
MRAM
Word
Courtesy S. Yuasa (AIST)
http://magnet.atp.tuwien.ac.at/gallery/mram/index.html
Race track memory
http://www.storageinsider.de/index.cfm?pid=3628&pk=98674&p=1
Parkin et al., Science, 390, 190 (2008)
Race track memory
Tail-tail DW
• Anticlockwise transverse DW
• Clockwise transverse
• Anticlockwise vortex structure
Increasing wire width
Pulses with neg. polarity
Head-to-head DW
Pulses with pos. polarity
Two DW in one wire
Parkin et al., Science, 390, 190(2008)
Exchange spring
Thick layers of soft
and hard magnet
Hard magnet switches
when
exchange energy ≈
anisotropy energy
Thin layers of soft and
hard magnet
http://en.wikipedia.org/wiki/Exchange_spring_magnet
AFM based spin valve
FC in +0.3T or -0.3T
Park et al. Nature Materials 10, 347(2011)