Magnetic Nanowires: Revolutionizing Hard Drives, Random Access Memory, & Cancer Treatment

By Beth Stadler

Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN

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Abstract

Magnetic nanowires can have many names: bits, sensors, heads, artificial cilia, sensors, and nano-bots. These applications require nanometer control of dimensions, while incorporating various metals and alloys. To realize this control, 7- to 200-nm diameter nanowires are synthesized within insulating matrices by direct electrochemistry. Our nanowires can easily have lengths 10,000x their diameters, and they are often layered with magnetic and non-magnetic metals as required by each application. This talk will reveal synthesis secrets for nm-control of layer thicknesses, even for difficult alloys, which has enabled studies of magnetization reversal, magneto-elasticity, giant magnetoresistance, and spin transfer torque switching. These nanowires will mitigate the ITRS Roadmap’s “Size Effect” Grand Challenge which identifies the high resistivities in small interconnects as a barrier to continued progress along Moore’s Law (or better). High magnetoresistance is also possible in other multilayered nanowires that exhibit excellent properties for mulit-level nonvolatile random access memory. If the insulating growth matrix is etched away, the nanowires resemble a magnetic bed of nano-seaweed which enables microfluidic flow sensors and vibration sensors. Finally, we have incubated various nanowires with several healthy and cancerous cell lines, and find that they are readily internalized. Careful magnetic design of these “nano-bots” enables external steering, nano-barcode identification, and several modes of therapy.

Bio

Bethanie Stadler Bethanie Stadler works on the integration of magnetic nanowires for magnetoelectronics (including hard drive heads), microfluidic flow sensors and actuators, acoustic/vibration sensor applications, and cellular biomarkers. In photonics, Stadler works on the integration of magnets, magneto-optical garnets waveguides, and nanostructures for magnetophotonic crystals with semiconductor platforms for isolator and sensor applications. Stadler received her PhD from MIT in 1994 and her B.S. from Case Western Reserve University in 1990. She held a National Research Council postodoctoral fellowship at the Air Force Rome Laboratory before joining Electrical and Computer Engineering at the University of Minnesota. Her research there has been awarded the NSF CAREER award and a McKnight Presidential Fellowship. Stadler has served as Director and Secretary of the international Materials Research Society.

Cite this work

Researchers should cite this work as follows:

  • Beth Stadler (2016), "Magnetic Nanowires: Revolutionizing Hard Drives, Random Access Memory, & Cancer Treatment," http://nanohub.org/resources/23620.

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Location

121 Burton Morgan, Purdue University, West Lafayette, IN

Tags

Magnetic Nanowires: Revolutionizing Hard Drives, Random Access Memory, & Cancer Treatment
  • Magnetic Nanowires Revolutionizing Hard Drives, Random Access Memory, & Cancer Treatment 1. Magnetic Nanowires Revolutioni… 0
    00:00/00:00
  • Magnetic Nanowires for: 2. Magnetic Nanowires for: 65.2318985652319
    00:00/00:00
  • Background: How to know the magnetic states? 3. Background: How to know the ma… 209.57624290957625
    00:00/00:00
  • Hysteresis Loop Measurement 4. Hysteresis Loop Measurement 307.80780780780782
    00:00/00:00
  • Hysteresis Loops 5. Hysteresis Loops 376.87687687687691
    00:00/00:00
  • First Order Reversal Curves (FORC) 6. First Order Reversal Curves (F… 878.04471137804478
    00:00/00:00
  • Resistance (MR and STT) 7. Resistance (MR and STT) 950.11678345011683
    00:00/00:00
  • Magneto-Resistance (MR) 8. Magneto-Resistance (MR) 958.32499165832508
    00:00/00:00
  • Spin Transfer Torque (STT) Switching 9. Spin Transfer Torque (STT) Swi… 1242.9095762429097
    00:00/00:00
  • TEM 10. TEM 1271.0710710710712
    00:00/00:00
  • Why Electrochemical Synthesis? 11. Why Electrochemical Synthesis? 1306.1394728061396
    00:00/00:00
  • Thin Film Growth 12. Thin Film Growth 1355.9893226559893
    00:00/00:00
  • Top Down- Lift off 13. Top Down- Lift off 1389.2892892892894
    00:00/00:00
  • Bottom up Nanofabrication: Grow devices in place 14. Bottom up Nanofabrication: Gro… 1454.4878211544879
    00:00/00:00
  • OXIDE Template 15. OXIDE Template 1496.1294627961295
    00:00/00:00
  • Anodization 16. Anodization 1499.1991991991993
    00:00/00:00
  • Anodic Alumina Templates 17. Anodic Alumina Templates 1555.9225892559227
    00:00/00:00
  • Two-step Nanoporous Anodic Alumina 18. Two-step Nanoporous Anodic Alu… 1591.1244577911245
    00:00/00:00
  • Directing the Self-Assembly 19. Directing the Self-Assembly 1672.2722722722724
    00:00/00:00
  • Untitled: Slide 20 20. Untitled: Slide 20 1680.0133466800135
    00:00/00:00
  • Untitled: Slide 21 21. Untitled: Slide 21 1857.5575575575576
    00:00/00:00
  • METAL Wires 22. METAL Wires 2009.7430764097433
    00:00/00:00
  • Making Nanowires 23. Making Nanowires 2056.48982315649
    00:00/00:00
  • Barcode Nanowires: Co, Cu, Ni, FeGa, Au.. any metal? 24. Barcode Nanowires: Co, Cu, Ni,… 2121.087754421088
    00:00/00:00
  • Synthesis secrets: nm-control of layer thicknesses 25. Synthesis secrets: nm-control … 2234.9683016349686
    00:00/00:00
  • Repeatability of Nanowire Dimensions 26. Repeatability of Nanowire Dime… 2400
    00:00/00:00
  • Controlled, Distinguishable Magnetic Properties 27. Controlled, Distinguishable Ma… 2471.6383049716383
    00:00/00:00
  • Applications 28. Applications 2544.3109776443112
    00:00/00:00
  • Areal Density vs Year 29. Areal Density vs Year 2591.1911911911911
    00:00/00:00
  • Perpendicular Recording 30. Perpendicular Recording 2603.9039039039039
    00:00/00:00
  • Large Lithography, Small Sensors 31. Large Lithography, Small Senso… 2609.0423757090425
    00:00/00:00
  • Critical Current Density agrees 32. Critical Current Density agree… 2726.8601935268603
    00:00/00:00
  • Random Access Memory no bias field required 33. Random Access Memory no bias f… 2754.2542542542542
    00:00/00:00
  • Applications 34. Applications 2765.765765765766
    00:00/00:00
  • Manipulation of Osteosarcoma cells with Au/Ni/Au nanowires 35. Manipulation of Osteosarcoma c… 2797.3306639973307
    00:00/00:00
  • DIC Imaging of cells targeted with peptide coated nanowires 36. DIC Imaging of cells targeted … 2810.9109109109108
    00:00/00:00
  • Surface modifications 37. Surface modifications 2818.184851518185
    00:00/00:00
  • Minimal cell death Metabolic activity 38. Minimal cell death Metabolic a… 2857.9579579579581
    00:00/00:00
  • Studying Internalization of peptide-conjugated nanowires 39. Studying Internalization of pe… 2884.1174507841174
    00:00/00:00
  • Cells dispersing cluster 40. Cells dispersing cluster 2905.4721388054722
    00:00/00:00
  • Nanowires self disperse by 4 means: 41. Nanowires self disperse by 4 m… 2919.285952619286
    00:00/00:00
  • Nanowires self disperse by 4 means: 42. Nanowires self disperse by 4 m… 2932.4324324324325
    00:00/00:00
  • Conclusions 43. Conclusions 2942.1755088421755
    00:00/00:00
  • Thanks! 44. Thanks! 2965.665665665666
    00:00/00:00