Defense Intelligence Reference Document Metallic Spintronics

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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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