Spin-Polarized Electron Transport through Nanometer-Scale Al Grains

L. Y. Zhang; C. Y. Wang; Y. G. Wei; X. Y. Liu; D. Davidovic

doi:10.1103/PhysRevB.72.155445

paper

Spin-Polarized Electron Transport through Nanometer-Scale Al Grains

arXiv:cond-mat/0502181 · doi:10.1103/PhysRevB.72.155445

Abstract

We investigate spin-polarized electron tunnelling through ensembles of nanometer scale Al grains embedded between two Co-reservoirs at 4.2K, and observe tunnelling-magnetoresistance (TMR) and effects from spin-precession in the perpendicular applied magnetic field (the Hanle effect). The spin-coherence time ( $T_{2}^{⋆}$ ) measured using the Hanle effect is of order $n s$ . The dephasing is attributed to electron spin-precession in local magnetic fields. Dephasing process does not destroy $T M R$ , which is strongly asymmetric with bias voltage. The asymmetric TMR is explained by spin relaxation in Al grains and asymmetric electron dwell times.

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