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Shot Noise in Magnetic Tunnel Junctions: Evidence for Sequential Tunneling

R. Guerrero·F. G. Aliev·Y. Tserkovnyak·T. S. Santos·J. S. Moodera
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Abstract

We report the experimental observation of sub-Poissonian shot noise in single magnetic tunnel junctions, indicating the importance of tunneling via impurity levels inside the tunnel barrier. For junctions with weak zero-bias anomaly in conductance, the Fano factor (normalized shot noise) depends on the magnetic configuration being enhanced for antiparallel alignment of the ferromagnetic electrodes. We propose a model of sequential tunneling through nonmagnetic and paramagnetic impurity levels inside the tunnel barrier to qualitatively explain the observations.

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R. Guerrero, F. G. Aliev, Y. Tserkovnyak, T. S. Santos, J. S. Moodera. 2007-01-16. Shot Noise in Magnetic Tunnel Junctions: Evidence for Sequential Tunneling. https://doi.org/10.1103/physrevlett.97.266602

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