Thin-film magnetic head with current-perpendicular-to-the plane

• US 20040114284A1
• Filed: 09/24/2003
• Published: 06/17/2004
• Est. Priority Date: 09/25/2002
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Matsuzaki, Mikio, Morita, Haruyuki, Rachid, Sbiaa
• Granted Patent: US 7,123,451 B2
• Time in Patent Office: Days
• US Class Current: 360/324.11
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/3116 Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks G11B5/3113, G11B5/245 take precedence
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: Y10T 29/49032 Fabricating head structure or component thereof

Abstract

The thin-film magnetic head of the present invention is provided with an antiferromagnetic layer, a pinned layer whose direction of magnetization is fixed by exchange-coupling with the antiferromagnetic layer, a free layer whose direction of magnetization varies according to external magnetic field, an intermediate layer disposed between the pinned layer and free layer, and a pair of electrode layers for supplying a sense current in a layer thickness direction of the free layer. One electrode layer is connected to the pinned layer. Due to this configuration, a sense current flows through the free layer, the intermediate layer, and the pinned layer, but basically does not flow through the antiferromagnetic layer. As a consequence, the antiferromagnetic layer does not contribute to total resistance of the magnetoresistance element, allowing a high magnetoresistance ratio to be obtained.

Claims

1. A thin-film magnetic head comprising:

an antiferromagnetic layer;

a pinned layer whose direction of magnetization is fixed by exchange-coupling with said antiferromagnetic layer;

a free layer whose direction of magnetization varies according to external magnetic field;

an intermediate layer disposed between said pinned layer and said free layer; and

a pair of electrode layers for supplying a sense current to the free layer in a layer thickness direction of said free layer,

one of said electrode layers being connected to said pinned layer.

2. A thin-film magnetic head according to claim 1, wherein said pinned layer comprises a first ferromagnetic layer in contact with said antiferromagnetic layer, a second ferromagnetic layer whose direction of magnetization is opposite to that of said first ferromagnetic layer, and a nonmagnetic spacer layer disposed between said first and second ferromagnetic layers;

said one electrode layer connected to said pinned layer being in contact with a track-width side face of said second ferromagnetic layer but not in contact with a track-width side face of said first ferromagnetic layer.

3. A thin-film magnetic head according to claim 2, wherein a face of said second ferromagnetic layer opposing said first ferromagnetic layer has an area smaller than that of a face of said first ferromagnetic layer opposing said second ferromagnetic layer.

4. A thin-film magnetic head according to claim 1, wherein said pinned layer, said intermediate layer, and said free layer are disposed between a substrate and said antiferromagnetic layer, and

the other electrode layer of said pair of electrode layers that is not connected to the pinned layer is disposed between said free layer and said substrate.

5. A thin-film magnetic head according to claim 1, wherein said intermediate layer is formed from an electrically conductive material.

6. A head gimbal assembly having a thin-film magnetic head mounted with a gimbal;

said thin-film magnetic head comprising;

an antiferromagnetic layer;

a pinned layer whose direction of magnetization is fixed by exchange-coupling with said antiferromagnetic layer;

a free layer whose direction of magnetization varies according to external magnetic field;

an intermediate layer disposed between said pinned layer and said free layer; and

a pair of electrode layers for supplying a sense current in a layer thickness direction of said free layer,

one of said electrode layers being connected to said pinned layer.

7. A hard disk apparatus comprising a hard disk adapted to write magnetic information therein, and a thin-film magnetic head for reading said magnetic information on said hard disk;

said thin-film magnetic head comprising;

an antiferromagnetic layer;

a pinned layer whose direction of magnetization is fixed by exchange-coupling with said antiferromagnetic layer;

a free layer whose direction of magnetization varies according to external magnetic field;

an intermediate layer disposed between said pinned layer and said free layer; and

a pair of electrode layers for supplying a sense current in a layer thickness direction of said free layer,

one of said electrode layers being connected to said pinned layer.

8. A method of making a thin-film magnetic head, said method comprising the steps of:

forming an antiferromagnetic layer;

forming a pinned layer whose direction of magnetization is fixed by exchange-coupling with said antiferromagnetic layer;

forming a free layer whose direction of magnetization varies according to external magnetic field;

forming an intermediate layer disposed between said pinned layer and said free layer; and

forming a pair of electrode layers for supplying a sense current to said free layer in a layer thickness direction of said free layer,

one of said electrode layers being formed so as to be connected to said pinned layer.

9. A method of making a thin-film magnetic head according to claim 8, wherein said pinned layer comprises a first ferromagnetic layer in contact with said antiferromagnetic layer, a second ferromagnetic layer whose direction of magnetization is opposite to that of said first ferromagnetic layer, and a nonmagnetic spacer layer disposed between said first and second ferromagnetic layers,

said one electrode layer connected to said pinned layer being formed in contact with a track-width side face of said second ferromagnetic layer but not in contact with a track-width side face of said first ferromagnetic layer.

10. A method of making a thin-film magnetic head according to claim 8, wherein said pinned layer comprises a first ferromagnetic layer in contact with said antiferromagnetic layer, a second ferromagnetic layer whose direction of magnetization is opposite to that of said first ferromagnetic layer, and a nonmagnetic spacer layer disposed between said first and second ferromagnetic layers;

said method comprising the steps of;

obtaining said first ferromagnetic layer;

forming a magnetic layer to become said second ferromagnetic layer so as to cover said first ferromagnetic layer; and

patterning said magnetic layer by utilizing a mask so as to obtain said second ferromagnetic layer having a desirable form;

wherein a projected area of said mask onto said first ferromagnetic layer is smaller than the area of a face of said first ferromagnetic layer opposing said mask.