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Defense Intelligence Reference Document Metallic Spintronics

Defense Intelligence Agency · 27 pages · text from the file's own layer

This Defense Intelligence Reference Document, dated 23 March 2010 and produced by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) program, is a technical report on metallic spintronics. It explains giant magnetoresistance, spin-transfer torque and antiferromagnetic spintronics, along with their uses in sensors, hard drive read heads and magnetic memory. It concludes that spintronic devices could enable low-power, radiation-resistant electronics suited to aerospace and long space missions.

  • p. 8 …Other sensor applications using GMR elements include monitoring of a ferrous gear rotation in machinery operation…
  • p. 11 …When current bias is reversed, the torque on fb will try to rotate Fb away from…
  • p. 17 …in angular momentum that occurs from the rotation of electrons spins. This spin-transfer torque can…
  • p. 19 …layer, leaving the Fl layer free to rotate at a lower field. The pinning is produced…
  • p. 20 …the "pinned" Fl layer, and its moment rotates to along -B, returning the 15 UNCLASSIFIED/ (FOR…
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Contents
1. Introduction .......................................................................................................... iv
2. Giant Mag netoresistance ..................................................................................... 1
2.1 GMR Basics ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• !!1••···························· 1
2.2 GM.R Applications .........................................~ .......................... ., ........................ 3
3. Spin-Transfer-Torque ......................................................................................... 4
3.1 STT. Basics .................................................................................................................. 4
3.2 STT Experiments ..................................................................................................................... 7
3. 3 STT Appllcat~ons ........................................................................................... 10
3,4 STT-Driven Motion of Magnetic Domain Walls ........................................... 12
4. Antiferromagnetic Metal Sl)lntro..nics ......................................................................•...... 12
4.1 Antiferromagnetic GMR ............................................................................. 13
4. 2 Antlferromag netlc STT................................................."' .................................... 14
5 .. Summary and Conclusion~ ................................................................................... 16
6 .. References .................... ,.................................................................................................. 18
Figures
Figure 1. In a Magnetic Multilayer, Several Atomic Layers of Magnetic Material
Alternate With Layers of Nonmagnetic Material ...................................... 1
Figure 2. Resistance of a Magnetic Multilayer R Versus Magnetic Field .................. 2
Figure 3. Differential Resistance dV/dl of a Mechanical Point Contact as a Fur,ction
of Current for a Series of Magnetic Fields................................................ 4
Figure 4. Device Schematics for STT Experiments ................................................. .
Figure 5. Qualitative Picture of STT ....................................................................................
Figure 6. Torques on a Magnetic Moment In a Magnetic Field and Subject to an
5
6
Electrical Current ....................................................................................... 7
Figure 7. Spin-Torque-Driven Magnetic Switching .................................................. 8
figure 8. Oscillatory Voltage .............................................................................................. 9
Figure 9. Scanning Transmission X-ray Microscopy Images ................................. 10
Figure 10. Conventional MRAM. Cell .............................................................................. 11
Flgu re 11. Racetrack Memory Co nee.pt .................................................................... 12
Figure 12. Schematic of Point Contact to Sample Geometry ................................. 15
iii
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 27 pages are in the text index: search them above, or from the library's search.