Negative tunneling magnetoresistance by canted magnetization in MgO/NiO tunnel barriers

Hyunsoo Yang, See Hun Yang, Dong Chen Qi, Andrivo Rusydi, Hiroyo Kawai, Mark Saeys, Titus Leo, David Smith, Stuart S P Parkin

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

The influence of the insertion of an ultrathin NiO layer between the MgO barrier and the ferromagnetic electrodes in magnetic tunnel junctions has been investigated from measurements of the tunneling magnetoresistance and via x-ray magnetic circular dichroism (XMCD). The magnetoresistance shows a high asymmetry with respect to bias voltage, giving rise to a negative value of up to -16% at 2.8K. We attribute this effect to the formation of noncollinear spin structures at the interface of the NiO layer as inferred from XMCD measurements. The magnetic moments of the interface Ni atoms tilt from their easy axis due to exchange coupling with the neighboring ferromagnetic electrode, and the tilting angle decreases with increasing NiO thickness. The experimental observations are further supported by noncollinear spin density functional calculations.

Original languageEnglish (US)
Article number167201
JournalPhysical Review Letters
Volume106
Issue number16
DOIs
StatePublished - Apr 19 2011

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Yang, H., Yang, S. H., Qi, D. C., Rusydi, A., Kawai, H., Saeys, M., Leo, T., Smith, D., & Parkin, S. S. P. (2011). Negative tunneling magnetoresistance by canted magnetization in MgO/NiO tunnel barriers. Physical Review Letters, 106(16), [167201]. https://doi.org/10.1103/PhysRevLett.106.167201