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arXiv · 1104.3403

The Kondo effect in magnetic impurities and ferromagnetic contacts

Hyunsoo Yang·See-Hun Yang·Grzegorz Ilnicki·Jan Martinek·Stuart S. P. Parkin
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Abstract

Planar macroscopic magnetic tunnel junctions exhibit well defined zero bias anomalies when a thin layer of ferromagnetic CoFe(B) nanodots is inserted within a MgO based tunnel barrier. The conductance curves exhibit a single and a double peak, respectively, for anti-parallel and parallel alignment of the magnetizations of the electrodes which sandwich the tunnel barrier. This leads to a suppression of the tunneling magnetoresistance near zero bias. We show that the double peak structure indicates that the zero-bias anomaly is spin-split due to a magnetic exchange interaction between the magnetic nanodots and the ferromagnetic electrodes. Using a model based on an Anderson quantum dot coupled to ferromagnetic leads, we show that these results imply the coexistence of a Kondo effect and ferromagnetism.

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Hyunsoo Yang, See-Hun Yang, Grzegorz Ilnicki, Jan Martinek, Stuart S. P. Parkin. 2011-04-18. The Kondo effect in magnetic impurities and ferromagnetic contacts. https://arxiv.org/abs/1104.3403

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