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Honolulu, Hawaii, United States, 2006/10/04 - Researchers in France describe the experimental achievement of a technique that allows to inject and detect spins in a single isolated nanometer-sized cluster.
Spintronics (short for "spin-based electronics") is an emergent technology which exploits the quantum propensity of electrons to spin as well as making use of their charge state. The field of spintronics got started in 1988 with the discovery ("Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices") of giant magnetoresistance effect in magnetic multilayers in which a single dimension was reduced to the nanometer range. The field was then extended to structures with two reduced dimensions like nanowires and nanopillars or nanotubes. Today, a challenge for spintronics is the study of spin transport properties in structures based on zero-dimensional elements in which the three dimensions have been reduced. So far, very few techniques allow to contact a single isolated nanometer sized object to study the effect of confinement on spin transport. Researchers in France now describe the experimental achievement of a technique that allows to inject and detect spins in a single isolated nanometer-sized cluster. They fabricated nanometer-sized magnetic tunnel junctions using a conductive tip nanoindentation technique in order to study the transport properties of a single metallic nanoparticle.
"We have developed an original process to investigate the spin transport properties of a single nanoparticle and provided evidence for its successful realization, "Dr. Pierre Seneor, assistant professor in the Unité Mixte de Physique laboratory at the University of Paris Sud, summarizes the findings for Nanowerk. "Our approach paves the way for a more in-depth study of magneto-Coulomb phenomena in nanosized clusters."
Seneor is co-author of a recent paper titled "Evidence for spin injection in a single metallic nanoparticle: A step towards nanospintronics" that was published in the August 7, 2006 issue of Applied Physics Letters. Two of the authors of the paper, Albert Fert and Frédéric Petroff, were part of the team that wrote the 1988 paper mentioned above.
"It is a real challenge to connect a single isolated 0D nanometer sized object to ferromagnetics leads for transport measurements" Seneor says. "Until now, only one result had been put forward ("The Kondo Effect in the Presence of Ferromagnetism"). Here we demonstrate a new method to connect such a small object to ferromagnetic leads without requiring high cost state of the art nanostructuration techniques."
While only two results are available up to now on connecting a 0D nano-object to ferromagnetic electrodes enabling spin polarized injection and detection, extensive theoretical studies have been undertaken, leaving the field wide open for experiments.
Read the full article on the Nanowerk website.
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By Michael Berger, Copyright 2006 Nanowerk LLC