Bit selection scheme and dipolar interactions in high density precessional MRAM

Bit selection scheme and dipolar interactions in high density precessional MRAM

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Precessional switching of the magnetisation is a convenient way to ensure sub-ns, reliable, energy cost efficient writing of an MRAM cell. In this technique, a controlled pulse of magnetic field is applied perpendicular to the easy magnetisation axis of the MRAM cell free layer, which switches the magnetisation from one direction to its reverse. Bit selection and fast direct overwrite can be obtained by superimposing another field pulse along the easy magnetisation axis. It is proposed to change the cell shape while reducing its size to postpone the onset of superparamagnetism. Based on the Landau-Lifshitz-Gilbert equation an analytical theory of this precessional switching process has been developed. This allows the understanding of the minimal switching field and accountingly for the bit selection scheme. A study of how the writing parameter window is affected by a distribution of cell parameters in a array and by the intercell dipolar coupling has been made. A high-pass encoding, and a balanced encoding algorithm are proposed to reduce the maximum intercell dipolar field.


    1. 1)
    2. 2)
      • J. Miltat , G. Aburquerque , A. Thiaville , B. Hillebrands , K. Ounadjela . (2001) Spin dynamics in confined magnetic structures I.
    3. 3)
      • J. Fassbender , B. Hillebrands , K. Ounadjela . (2003) Spin dynamics in confined magnetic structures II.
    4. 4)
      • Gerrits Th , H.A.M. Van Den Berg , J. Hohlfeld , L. Bär , Rasing Th. . Ultrafast precessional magnetization reversal by picosecond magnetic field pulse shaping. Nature
    5. 5)
      • S. Kaka , S.E. Russek . Precessional switching of submicrometer spin-valves. Appl. Phys. Lett.
    6. 6)
    7. 7)
    8. 8)
    9. 9)
    10. 10)
      • E.C. Stoner , E.P. Wohlfarth . A mechanism of magnetic hysteresis in heterogeneous alloys. Philos. Trans. R. Soc. Lond. A
    11. 11)
      • L. Landau , E. Lifchitz . On the theory of the dispersion of magnetic permeability in ferromagnetic bodies. Phys. Z Sowjetunion.
    12. 12)
      • T.L. Gilbert . A Lagrangian formulation of the gyromagnetic equation of the magnetization field. Phys. Rev.
    13. 13)
      • C. Serpico , I.D. Mayergoyz , G. Bertotti . Analytical solutions of Landau–Lifshitz equation for precessional switching. J. Appl. Phys. , 10
    14. 14)
    15. 15)
      • Section 9.6 of Fontolliet, P.G.: ‘Traité d’électricité volume 18: Systèmes de télécommunications’ (Presses polytechniques et universitaires romandes Editors).
    16. 16)
      • G.W. Burr , J. Ashley , H. Coufal , R.K. Grygier , J.A. Hoffnagle , C.M. Jefferson , B. Marcus . Modulation coding for pixel-matched holographic data storage. Opt. Lett. , 639 - 641
    17. 17)
      • G.W. Burr , W.C. Chou , M.A. Neifeld , H. Coufal , J.A. Hoffnagle , C.M. Jefferson . Experimental evaluation of user capacity in holographic data storage systems. Appl. Opt. , 5431 - 5443

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