Shot Noise in Magnetic Tunnel Junctions: Evidence for Sequential Tunneling

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.

5 pages, 5 figures

References in corpus (2)

• Currents, Torques, and Polarization Factors in Magnetic Tunnel Junctions
• Theory of Zero-Bias Anomaly in Magnetic Tunnel Junctions: Inelastic Tunneling via Impurities

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