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

Abstract

The influence of the magnetization configuration on Kondo effect in magnetic tunnel junction is investigated. In the parallel configuration, an additional resistance contribution (R*) below 40 K exhibits a logarithmic temperature dependence, indicating the presence of Kondo effect. However, in the anti-parallel configuration, the Kondo-effect-associated spin-flip scattering has a nontrivial contribution to the tunneling current, which compensates the reduction of the current directly caused by Kondo scattering, making R* disappear. These results indicate that suppression and restoration of Kondo effect can be experimentally achieved by altering the magnetization configuration, enhancing our understanding of the role of Kondo effect in spin-dependent transport.

Exchange bias study of sub-100 nm-diameter CoFeB/IrMn antidot and nanodot arrays fabricated by nanosphere lithography

“…This phenomenon is broadly known as the exchange bias effect. Benefited from the enhanced coercivity (Hc) and the loop shift (Hex) [2], the exchange bias effect has brought great flexibility in tailoring the magnetization reversal properties of the reference layers in spin valves [3,4]. Ever since the primary discovery in CoO coated Co particles [5], intense research have been conducted to reveal the influencing factors of exchange bias, such as thin film composition [6,7], layer thickness [6,8], applied field angle [9], field cooling [10,11], ion-beam bombardment [12], and post annealing [13,14].…”