Controlling the demagnetizing field of an in-plane free layer by exchange coupling with a perpendicular multilayer

Yong Chang Lau, Kaan Oguz, Karsten Rode, J. M.D. Coey

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

The demagnetizing field of a Co50Fe50 free layer in an in-plane micron-sized magnetic tunnel junction (MTJ) can be partially compensated by exchange coupling with a [Co90Fe10/Pt] N multilayer with perpendicular magnetic anisotropy via a Ru interlayer. The perpendicular anisotropy for N = 5 is optimized for nominal CoFe and Pt thickness of 0.4 nm and 1.0 nm, respectively. An increase of tunnel magnetoresistance (TMR) from 2% to 75% is observed in MTJs as the free layer thickness, t varies from 1.0 nm to 3.0 nm. A phenomenological model is developed to interpret the TMR dependence in terms of the free layer magnetization rotation from in-plane to out-of-plane with decreasing t, a consequence of interlayer exchange coupling with the perpendicular multilayer. We suggest that this strategy could significantly reduce the switching current density in such MTJs.

Original languageEnglish
Article number110
JournalEuropean Physical Journal B
Volume86
Issue number3
DOIs
Publication statusPublished - 2013 Mar
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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