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Nanomagnetics

Nanomagnetics. Most people relate magnetics to storage. Magnetic storage: currently 100 Mbits/in 2 at the expected 10 Gbits/in 2 an individutal bit will be 1000 nm wide by 70 nm long. .

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Nanomagnetics

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  1. Nanomagnetics

  2. Most people relate magnetics to storage. Magnetic storage: currently 100 Mbits/in2 at the expected 10 Gbits/in2 an individutal bit will be 1000 nm wide by 70 nm long.

  3. One bitviewed bymagnetic force microscopyIs it nano?Well, overall size is ~1mm, but the bit has smaller details.Clearly, nano characterization methods are being used to see this.

  4. Quaternary structure of the protein. The pieces make an open cavity that can store thousands of Fe atoms. Apoferritin, your body’s iron storage protein and precision magnetic system.

  5. Types of Magnetism (Sibel Turksen Thesis)

  6. Few subjects are more difficult to understand than magnetism. Encyclopedia Britannica

  7. M Magnetization -M Magnetization in opposite direction General Hysteresis Plot • Perfect Superparamagnet

  8. Paramagnet, Ferromagnet & Superparamagnet

  9. Right or wrong…. I think of the superparamagnet as a small ferromagnet. Because of its small size, the magnetic moment wanders. When given an order to align (when a magnetic field is imposed) it aligns with the same enthusiasm that a ferromagnet has, which exceeds that of the paramagnet. Ferromagnet Superparamagnet Paramagnet Zero field Applied field Like the paramagnet, the superparamagnet returns to zero magnetization when the field is removed. It does so for a different reason: small size, not intrinsically weak exchange between the individual moments.

  10. The bottom line is: Nano scale has a big impact on the magnetic properties! In a normally ferromagnetic material, nano scale reduces the moment, but it can be restored by applying a magnetic field. The good news: switchable interactions! The bad news: There would seem to be a lower limit to the size of a magnetic particle that can hold an alignment for data storage.

  11. N N N N S S S S Suppose some particles do have magnetic moments. They will chain together! The chain causes high viscosity.  Magnetorheological effect.

  12. Magnetorheological Effect

  13. A magnetic fluid.

  14. Fluid becomes solid—and reverses!

  15. Just pretty.

  16. Applications to cars.

  17. Civil Engineering Application Dong Ting Lake Bridge -- China

  18. Health and Home Appliance Applications

  19. Optical Applications

  20. Optical Application Results Smooth to ~30 nm i.e., l/20 @ l =600 nm How can this be used? Better lasers? Better laser weapons? Better chances for cheap, pollution-free nuclear fusion energy?

  21. Conclusion • It is hard not to be excited about magnetic particles! • Nice convergence of fairly simple chemistry and tangible materials science. • Tomorrow, I will show you the idea we had for getting into this field.

  22. References Nanotechnology, edited by G.L. Timp, Springer-Verlag, New York, 1998; Chapter 12 by Awschawlom and von Molnar, “Physical Properties of Nanoscale Magnets”. Lord Corporation Website. Center for Optics Manufacturing. Sibel Turksen Ph.D. Thesis, LSU, 2005.

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