Interplay between superconductivity and the Kondo effect on magnetic nanodots

Hyunsoo Yang, Mahn Soo Choi, Grzegorz Ilnicki, Jan Martinek, See Hun Yang, Stuart Parkin

Research output: Contribution to journalArticlepeer-review

Abstract

We study the interplay of superconductivity, ferromagnetism, and the Kondo effect in a single system, using vertical geometry and planar magnetic tunnel junction devices, in which a thin CoFe layer is inserted in the middle of the MgO layer, forming a quantum dot like system. It is shown that the Kondo resonance peak at the zero bias coexists with a sharp Bardeen-Cooper-Schrieffer gap on double tunnel junctions, Al/MgO/CoFe nanodot/MgO/Al. It is also found that the competition between superconductivity and the Kondo effect is tunable with magnetic fields and the temperature. The coexistence of Kondo screening and superconductivity survives long range magnetic order in CoFe nanodots with a spin polarization of 0.2; however, it disappears when the CoFe layer becomes a continuous film with a spin polarization of 0.5. The competition between SC and the Kondo effect in the presence of magnetic ordering opens exciting possibilities to control information in nanomagnets.

Original languageEnglish
Article number152407
JournalApplied Physics Letters
Volume118
Issue number15
DOIs
Publication statusPublished - 2021 Apr 12

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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