Zero-Bias Anomaly in Magnetic Tunnel Junctions

Abstract

We present experimental results, which may indicate the possibility of the coexistence of the Kondo effect and ferromagnetism in macroscopic planar magnetic tunnel junctions with a layer of nanodots inside tunnel barriers. A conductance double peak structure was observed. Magnetic field dependence of the splitting of a conductance peak, and temperature evolution of the conductance curves are well explained from the theoretical point of view according to the predictions of the Kondo physics and cotunneling in the Anderson quantum dot coupled to ferromagnetic leads.

Kondo effect in magnetic tunnel junctions with an AlO x tunnel barrier

“…When the magnetic impurities are formed in the ferromagnetic layer or at the interface between one ferromagnetic layer and the barrier, the conduction electrons tend to be scattered by these impurities, giving rise to an increase of the resistance [7,9]. When the magnetic impurities are formed inside the barrier, additive resonant channels are possibly activated, resulting in a reduction in the junction resistance [10,20]. The rapid rise of the resistance in this MTJ is consistent with the former case.…”