[Triumf-seminars] TRIUMF Special Seminar today at 16:00

[TRIUMF Seminars]

Date/Time: Fri 2015-11-20 at 16:00

Location:  Auditorium          

Speaker:   Bethanie Stadler (U Minnesota)

Title:     IEEE Seminar - Magnetic Nanowires: Revolutionizing Hard Drives, RAM, and Cancer Treatment

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, our 7- to 200-nm diameter nanowires are synthesized within insulating matrices by direct electrochemistry, which negates sidewall damage such as that caused by lithographical patterning of vacuum-deposited structures. Our nanowires can easily have lengths 10,000x their diameters, and they are often layered with magnetic (Co, Fe, FeGa, FeNi, Ni) and non-magnetic (Ag, Cu, Au) 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 (GMR), and spin transfer torque (STT) switching. In addition, this lithography-free synthesis yields 10-nm diameter nanowires that have resistivities of only 5.4e-6 Ohm cm (nearly that of bulk copper) due to negligible sidewall roughness. Therefore, 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). Ten-nm diameter trilayers of [Co(15nm)/Cu(5nm)/Co(10nm)] have also met or surpassed all of the criterion for the world’s smallest read heads with 30 Ohm resistance and 19% magnetoresistance.  High magnetoresistance is also possible in other multilayered nanowires that exhibit excellent properties for mulit-level nonvolatile random access memory (RAM) using STT switching at very low current densities (100kA/cm2).  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 by al
l cell types thus far.  Careful magnetic design of these "nano-bots" enables external steering, nano-barcode identification, and several modes of therapy. In short, by the end of this talk, I hope you will be convinced that magnetic nanowires can and will revolutionize hard drives, RAM, and cancer treatment.



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