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arXiv · 2106.11274

Negative correlation between the linear and the nonlinear conductance in magnetic tunnel junctions

Shuichi Iwakiri·Satoshi Sugimoto·Yasuhiro Niimi·Yusuke Kozuka·Yukiko K. Takahashi·Shinya Kasai·Kensuke Kobayashi
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Abstract

The current-voltage ($IV$) characteristics beyond the linear response regime of magnetic tunnel junction (MTJ) is systematically investigated. We find a clear negative correlation between the two coefficients to characterize the linear ($I$$\propto$$V$) and the lowest-order nonlinear ($I$$\propto$$V^3$) currents, which holds regardless of the temperature and the thickness of the tunnel barrier. This observation cannot simply be explained by the standard tunneling model such as the Brinkman model, suggesting a mechanism intrinsic to MTJ. We propose a phenomenological model based on the Julli\'ere model that attributes the observed negative correlation to the spin-flip tunneling assisted by a magnon. These results suggest a fundamental law between the linear and the nonlinear response of MTJ.

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Shuichi Iwakiri, Satoshi Sugimoto, Yasuhiro Niimi, Yusuke Kozuka, Yukiko K. Takahashi, Shinya Kasai, Kensuke Kobayashi. 2021-06-21. Negative correlation between the linear and the nonlinear conductance in magnetic tunnel junctions. https://doi.org/10.1103/physrevb.103.245427

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