Spin-valve type magnetoresistive thin film element comprising free magnetic layer having nife alloy layer
First Claim
1. A spin-valve type magnetoresistive thin film element comprising:
- a antiferromagnetic layer;
a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization direction of the pinned magnetic layer being fixed by an anisotropic exchange magnetic field exchanged with the antiferromagnetic layer;
a nonmagnetic electrically conductive layer formed between the pinned magnetic layer and a free magnetic layer;
a bias layer for orienting the magnetization of the free magnetic layer to a direction intersecting the magnetization direction of the pinned magnetic layer; and
an electrically conductive layer for supplying a sensing current to the pinned magnetic layer, the nonmagnetic electrically conductive layer and the free magnetic layer;
wherein the free magnetic layer comprises a NiFe alloy film and has a thickness in a range of 30 to 100 angstrom, wherein said antiferromagnetic layer comprises two antiferromagnetic layers, one of said two antiferromagnetic layers being formed above and the other of said two antiferromagnetic layers being formed below the free magnetic layer, and wherein the NiFe alloy film, as the constituent of the free magnetic layer, has a Ni content in a range of 81.7 to 84 atomic percent.
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Abstract
A spin-valve type magnetoresistive thin film element includes at least one antiferromagnetic layer, a pinned magnetic layer in contact with the antiferromagnetic layer, a nonmagnetic electrically conductive layer formed on the pinned magnetic layer, with a free magnetic layer formed thereon, a bias layer for orienting the magnetization of the free magnetic layer to a direction intersecting the magnetization direction of the pinned magnetic layer, and an electrically conductive layer for supplying a sensing current to the pinned magnetic layer, the nonmagnetic electrically conductive layer and the free magnetic layer. The free magnetic layer is composed of a NiFe alloy film and has a thickness in a range of 30 to 100 Å. When the composition of the NiFe alloy is properly determined, the magnetostriction constant of the free magnetic layer can be controlled to be −2×10−6to 1×10−6, and more preferably −0.5×10−6 to 0, resulting in reduced anisotropic dispersion due to height direction due to the magnetoelastic effect. The element has reduced Barkhausen noise and a high rate of change in resistance.
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Citations
21 Claims
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1. A spin-valve type magnetoresistive thin film element comprising:
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a antiferromagnetic layer;
a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization direction of the pinned magnetic layer being fixed by an anisotropic exchange magnetic field exchanged with the antiferromagnetic layer;
a nonmagnetic electrically conductive layer formed between the pinned magnetic layer and a free magnetic layer;
a bias layer for orienting the magnetization of the free magnetic layer to a direction intersecting the magnetization direction of the pinned magnetic layer; and
an electrically conductive layer for supplying a sensing current to the pinned magnetic layer, the nonmagnetic electrically conductive layer and the free magnetic layer;
wherein the free magnetic layer comprises a NiFe alloy film and has a thickness in a range of 30 to 100 angstrom, wherein said antiferromagnetic layer comprises two antiferromagnetic layers, one of said two antiferromagnetic layers being formed above and the other of said two antiferromagnetic layers being formed below the free magnetic layer, and wherein the NiFe alloy film, as the constituent of the free magnetic layer, has a Ni content in a range of 81.7 to 84 atomic percent. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A spin-valve type magnetoresistive thin film element comprising:
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a antiferromagnetic layer;
a pinned magnetic layer in contact with the antiferromagnetic layer, the magnetization direction of the pinned magnetic layer being fixed by an anisotropic exchange magnetic field exchanged with the antiferromagnetic layer;
a nonmagnetic electrically conductive layer formed between the pinned magnetic layer and a free magnetic layer;
a bias layer for orienting the magnetization of the free magnetic layer to a direction intersecting the magnetization direction of the pinned magnetic layer; and
an electrically conductive layer for supplying a sensing current to the pinned magnetic layer, the nonmagnetic electrically conductive layer and the free magnetic layer;
wherein the free magnetic layer comprises a layered structure of a NiFe alloy film and a metallic cobalt or cobalt alloy film and has a thickness in a range of 30 to 100 angstrom, the ratio of the thickness of said metallic cobalt or cobalt alloy film to the thickness of the free magnetic layer being in a range of 0 to 0.5, wherein said antiferromagnetic layer comprises two antiferromagnetic layers, one of said two antiferromagnetic layers being formed above and the other of said two antiferromagnetic layers being formed below the free magnetic layer, and wherein the NiFe alloy film, as the constituent of the free magnetic layer, has a Ni content in a range of 81 to 83.7 atomic percent. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification