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L'équipe de l'Institut Jean Lamour en charge de la priorité scientifique"Matériaux Artificiels Nanostructurés", accueille Bethanie Stadler (ECE Department, University of Minnesota) pour un séminaire intitulé :
"Magnetic Nanowires:Revolutionizing Hard Drives, RAM, and Cancer Treatment"
Date et lieu :
Jeudi 21 Mai 2015 à 11h00
Institut Jean Lamour
Faculté des Sciences et Technologies de Vandœuvre-lès-Nancy
Salle de séminaire (4eme étage)
Magnetic nanowires can have many names: bits, sensors, heads, artificial cilia, sensors, and nano-bots. Theseapplications require nanometer control of dimensions, while incorporating various metals and alloys. Torealize this control, our 7- to 200-nm diameter nanowires are synthesized within insulating matrices by directelectrochemistry, which negates sidewall damage such as that caused by lithographical patterning of vacuumdepositedstructures. Our nanowires can easily have lengths 10,000x their diameters, and they are often layeredwith magnetic (Co, Fe, FeGa, FeNi, Ni) and non-magnetic (Ag, Cu, Au) metals as required by eachapplication. 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), andspin transfer torque (STT) switching. In addition, this lithography-free synthesis yields 10-nm diameternanowires that have resistivities of only 5.4mW.cm (nearly that of bulk copper) due to negligible sidewallroughness. Therefore, these nanowires will mitigate the ITRS Roadmap’s “Size Effect” Grand Challengewhich identifies the high resistivities in small interconnects as a barrier to continued progress along Moore’sLaw (or better). Ten-nm diameter trilayers of [Co(15nm)/Cu(5nm)/Co(10nm)] have also met or surpassed allof the criterion for the world’s smallest read heads with 30 Ω resistance and 19% magnetoresistance. Highmagnetoresistance is also possible in other multilayered nanowires that exhibit excellent properties for mulitlevelnonvolatile 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-seaweedwhich enables microfluidic flow sensors and vibration sensors. Finally, we have incubated various nanowireswith several healthy and cancerous cell lines, and find that they are readily internalized by all cell types thusfar. Careful magnetic design of these “nano-bots” enables external steering, nano-barcode identification, andseveral modes of therapy. In short, by the end of this talk, I hope you will be convinced that magneticnanowires can and will revolutionize hard drives, RAM, and cancer treatment.