Enhanced spin accumulation and novel magnetotransport in nanoparticles.
Spin injection and accumulation are key phenomena supporting a variety of concepts for spin-electronic devices. These phenomena are expected to be enhanced in nanoparticles over bulk structures due to their discrete energy levels and large charging energies. In this article, precise magnetotransport measurements in the single-electron tunnelling regime are performed by preparing appropriate microfabricated devices containing cobalt nanoparticles. Here we provide experimental evidence for characteristic features of spin accumulation in magnetic nanoparticles, such as oscillations of the magnetoresistance with a periodical sign change as a function of bias voltage. Theoretical analysis of the magnetoresistance behaviour clearly shows that the spin-relaxation time in nanoparticles is highly enhanced in comparison with that in the bulk.
Yakushiji
Kay
K
Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. kyaku@imr.tohoku.ac.jp
Ernult
Franck
F
Imamura
Hiroshi
H
Yamane
Kazutaka
K
Mitani
Seiji
S
Takanashi
Koki
K
Takahashi
Saburo
S
Maekawa
Sadamichi
S
Fujimori
Hiroyasu
H
D003035:Cobalt; D004583:Electrons; D008280:Magnetics; D008962:Models, Theoretical; D049329:Nanostructures
D003035:Cobalt