Exchange-coupled film, method for making exchange-coupled film, and magnetic sensing element including exchange-coupled film
First Claim
1. An exchange-coupled film comprising a seed layer, an antiferromagnetic layer, and a ferromagnetic layer disposed in that order from the bottom, magnetization of the ferromagnetic layer being directed in a predetermined direction by an exchange coupling magnetic field generated at an interface between the antiferromagnetic layer and the ferromagnetic layer, wherein the seed layer is a metal layer having a thickness that is smaller than or equal to a critical thickness and having a crystalline phase which extends through from an upper surface to a lower surface of the seed layer.
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Abstract
An exchange-coupled film includes a seed layer, an antiferromagnetic layer, and a ferromagnetic layer. The seed layer is formed at a thickness that is larger than the critical thickness, and the thickness of the seed layer is then decreased by etching so as to be smaller than or equal to the critical thickness. Thereby, a crystalline phase which extends through the seed layer from the upper surface to the lower surface can be formed, and/or the average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer can be set to be larger than the thickness of the seed layer. Consequently, a large exchange coupling magnetic field Hex can be generated between the antiferromagnetic layer and the ferromagnetic layer.
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Citations
28 Claims
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1. An exchange-coupled film comprising a seed layer, an antiferromagnetic layer, and a ferromagnetic layer disposed in that order from the bottom, magnetization of the ferromagnetic layer being directed in a predetermined direction by an exchange coupling magnetic field generated at an interface between the antiferromagnetic layer and the ferromagnetic layer,
wherein the seed layer is a metal layer having a thickness that is smaller than or equal to a critical thickness and having a crystalline phase which extends through from an upper surface to a lower surface of the seed layer.
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2. An exchange-coupled film comprising a seed layer, an antiferromagnetic layer, and a ferromagnetic layer disposed in that order from the bottom, the magnetization of the ferromagnetic layer being directed in a predetermined direction by an exchange coupling magnetic field generated at an interface between the antiferromagnetic layer and the ferromagnetic layer,
wherein the seed layer is a metal layer having a thickness that is smaller than or equal to a critical thickness and having a crystalline phase, and an average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer is larger than a thickness of the seed layer.
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5. An exchange-coupled film comprising a seed layer, an antiferromagnetic layer, and a ferromagnetic layer disposed in that order from the bottom, the magnetization of the ferromagnetic layer being directed in a predetermined direction by an exchange coupling magnetic field generated at an interface between the antiferromagnetic layer and the ferromagnetic layer,
wherein the seed layer comprises a NiCr alloy or a NiFeCr alloy, the Cr content in the NiCr alloy or the NiFeCr alloy being 35 to 60 atomic percent; - and
wherein a thickness of the seed layer is smaller than or equal to a critical thickness. - View Dependent Claims (8, 9)
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17. A method for making an exchange-coupled film comprising the steps of:
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(a) forming a seed layer at a thickness that is larger than a critical thickness so that a crystalline phase extends through from a upper surface to a lower surface of the seed layer;
(b) etching the upper surface of the seed layer so that the thickness of the seed layer is smaller than or equal to the critical thickness; and
(c) depositing an antiferromagnetic layer and a ferromagnetic layer on the seed layer. - View Dependent Claims (19, 20, 22, 23, 25, 26, 27)
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18. A method for making an exchange-coupled film comprising the steps of:
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(d) forming a seed layer with a crystalline phase at a thickness that is larger than a critical thickness;
(e) etching a surface of the seed layer so that the thickness of the seed layer is smaller than or equal to the critical thickness and so that an average size, in a direction parallel to the layer surface, of the crystal grains in the seed layer is larger than the thickness of the seed layer; and
(f) depositing an antiferromagnetic layer and a ferromagnetic layer on the seed layer.
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21. A method for making an exchange-coupled film comprising the steps of:
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(g) forming a seed layer at a thickness that is larger than a critical thickness with a NiCr alloy or a NiFeCr alloy having a Cr content of 35 to 60 atomic percent;
(h) etching a surface of the seed layer so that the thickness of the seed layer is smaller than or equal to the critical thickness; and
(i) depositing an antiferromagnetic layer and a ferromagnetic layer on the seed layer. - View Dependent Claims (24)
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28. A method for making an exchange-coupled film comprising the steps of:
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(a) forming a seed layer at a thickness that is larger than a critical thickness so that a crystalline phase extends through from an upper surface to a lower surface of the seed layer;
(b) etching the upper surface of the seed layer so that the thickness of the seed layer is smaller than or equal to the critical thickness; and
(j) depositing a ferromagnetic layer on the seed layer.
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Specification