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CPP GMR and magnetostriction improvement by laminating Co90Fe10free layer with thin Fe50Co50layers

  • US 7,141,314 B2
  • Filed: 02/25/2004
  • Issued: 11/28/2006
  • Est. Priority Date: 02/25/2004
  • Status: Expired due to Fees
First Claim
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1. A current-perpendicular-to-plane (CPP) giant magnetoresistive (GMR) magnetic field sensor of the synthetic spin valve type comprising:

  • a substrate;

    a seed layer formed on the substrate;

    an antiferromagnetic pinning layer formed on the seed layer;

    a synthetic antiferromagnetic pinned layer formed on the pinning layer, said pinned layer further comprising ferromagnetic layer AP2, formed on said pinning layer, a non-magnetic coupling layer formed on AP2 and ferromagnetic layer AP1 formed on said coupling layer;

    a spacer layer formed on said AP1 layer;

    a laminated free layer formed on said spacer layer, the free layer including a plurality of layers of a second ferromagnetic material, each said layer being formed to a thickness between approximately 2.5 and 15 angstroms and each said layer being separated from an adjacent said layer by a lamina of a first ferromagnetic material formed to a thickness less than approximately 3 angstroms or by a Cu spacer layer formed to a thickness between approximately 1 and 4 angstroms; and

    wherein each said lamina of said first ferromagnetic material has a positive coefficient of magnetostriction and each said layer of said second ferromagnetic material has a negative coefficient of magnetostriction, whereby the coefficient of magnetostriction of said free layer can be made positive or negative, wherein said laminated free layer includes at least one lamina of said first ferromagnetic material; and

    a capping layer formed on said free layer.

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