US 6,636,397 B2 · Lead overlay spin valve sensor with antiferromagnetic layers in passive regions for stabilizing a free layer

Abstract

First and second hard bias layers abut first and second side surfaces of a spin valve sensor and first and second lead layers are connected to the sensor for conducting a sense current transversely therethrough. The spin valve sensor has a transverse length between the first and second side surfaces which is divided into a track width region between first and second passive regions wherein the track width region is defined by a space between the first and second lead layers. A free layer in the sensor has first and second passive portions in the first and second passive regions and the first and second passive portions have first and second surfaces respectively. First and second antiferromagnetic (AFM) layers are exchange coupled to the first and second surfaces of the free layer for longitudinally biasing the first and second passive portions of the free layer.

Drawings

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Drawings

Claims25

Dependent claims

A magnetic read head which has an air bearing surface (ABS), comprising:

a spin valve sensor including:
a ferromagnetic pinned layer that has a magnetic moment;
a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
a free layer;
and
a nonmagnetic electrically conductive spacer layer located between the free layer and the pinned layer structure;
the spin valve sensor being partially bounded by top and bottom surfaces and first and second side surfaces which intersect the ABS;
first and second hard bias layers abutting the first and second side surfaces respectively of the spin valve sensor;
first and second lead layers connected to the spin valve sensor for conducting a sense current transversely therethrough;
the spin valve sensor having a transverse length between the first and second side surfaces which is divided into a track width region between first and second passive regions wherein the track width region is defined by a space between said first and second lead layers;
the free layer having first and second passive portions in the first and second passive regions which have first and second surfaces respectively;
and
first and second antiferromagnetic (AFM) layers exchange coupled to said first and second surfaces for longitudinally biasing the first and second passive portions of the free layer.

10 more elements

A magnetic head assembly having an air bearing surface (ABS), comprising:

a write head including:
ferromagnetic first and second pole piece layers that have a yoke portion located between a pole tip portion and a back gap portion;
a nonmagnetic write gap layer located between the pole tip portions of the first and second pole piece layers;
an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
and
the first and second pole piece layers being connected at their back gap portions;
and
a read head including:
a spin valve sensor;
nonmagnetic electrically nonconductive first and second read gap layers;
the spin valve sensor being located between the first and second read gap layers;
a ferromagnetic first shield layer;
and
the first and second gap layers being located between the first shield layer and the first pole piece layer;
and
the spin valve sensor including:
a ferromagnetic pinned layer that has a magnetic moment;
a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
a free layer;
and
a nonmagnetic electrically conductive spacer layer located between the free layer and the pinned layer;
the spin valve sensor being partially bounded by top and bottom surfaces and first and second side surfaces which intersect the ABS;
first and second hard bias layers abutting the first and second side surfaces respectively of the spin valve sensor;
first and second lead layers connected to the spin valve sensor for conducting a sense current transversely therethrough;
the spin valve sensor having a transverse length between the first and second side surfaces which is divided into a track width region between first and second passive regions wherein the track width region is defined by a space between said first and second lead layers;
the free layer having first and second passive portions in the first and second passive regions which have first and second surfaces respectively;
and
first and second antiferromagnetic (AFM) layers exchange coupled to said first and second surfaces for longitudinally biasing the first and second passive portions of the free layer.

25 more elements

A magnetic disk drive including at least one magnetic head assembly that has an air bearing surface (ABS)and that includes a write head and a read head, comprising:

a write head including:
ferromagnetic first and second pole piece layers that have a yoke portion located between a pole tip portion and a back gap portion;
a nonmagnetic write gap layer located between the pole tip portions of the first and second pole piece layers;
an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
and
the first and second pole piece layers being connected at their back gap portions;
and
a read head including:
a spin valve sensor;
nonmagnetic electrically nonconductive first and second read gap layers;
the spin valve sensor being located between the first and second read gap layers;
a ferromagnetic first shield layer;
and
the first and second read gap layers being located between the first shield layer and the first pole piece layer;
and the spin valve sensor including:
a ferromagnetic pinned layer that has a magnetic moment;
a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
a free layer;
and
a nonmagnetic electrically conductive spacer layer located between the free layer and the pinned layer;
the spin valve sensor being partially bounded by top and bottom surfaces and first and second side surfaces which intersect the ABS;
first and second hard bias layers abutting the first and second side surfaces respectively of the spin valve sensor;
first and second lead layers connected to the spin valve sensor for conducting a sense current transversely therethrough;
the spin valve sensor having a transverse length between the first and second side surfaces which is divided into a track width region between first and second passive regions wherein the track width region is defined by a space between said first and second lead layers;
the free layer having first and second passive portions in the first and second passive regions which have first and second surfaces respectively;
first and second antiferromagnetic (AFM) layers exchange coupled to said first and second surfaces for longitudinally biasing the first and second passive portions of the free layer;
a housing;
a magnetic disk rotatably supported in the housing;
a support mounted in the housing for supporting the magnetic head assembly with said ABS facing the magnetic disk so that the magnetic head assembly is in a transducing relationship with the magnetic disk;
a spindle motor for rotating the magnetic disk;
an actuator positioning means connected to the support for moving the magnetic head assembly to multiple positions with respect to said magnetic disk;
and
a processor connected to the magnetic head assembly, to the spindle motor and to the actuator for exchanging signals with the magnetic head assembly, for controlling movement of the magnetic disk and for controlling the position of the magnetic head assembly.

30 more elements

A method of making a magnetic read head which has an air bearing surface (ABS), comprising the steps of:

a making a spin valve sensor comprising the steps of:
forming a ferromagnetic pinned layer that has a magnetic moment;
forming a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
forming a free layer;
and
forming a nonmagnetic electrically conductive spacer layer located between the free layer and the pinned layer;
forming the spin valve sensor with top and bottom surfaces and first and second side surfaces which intersect the ABS;
forming first and second hard bias layers abutting the first and second side surfaces respectively of the spin valve sensor;
forming first and second lead layers connected to the spin valve sensor for conducting a sense current transversely therethrough;
forming the spin valve sensor with a transverse length between the first and second side surfaces which is divided into a track width region between first and second passive regions wherein the track width region is defined by a space between said first and second lead layers;
forming the free layer with first and second passive portions in the first and second passive regions which have first and second surfaces respectively;
forming first and second antiferromagnetic (MM) layers exchange coupled to said first and second surfaces for longitudinally biasing the first and second passive portions of the free layer.

9 more elements

A method of making magnetic head assembly that has an air bearing surface (ABS), comprising the steps of:

making a write head including the steps of:
forming ferromagnetic first and second pole piece layers in pole tip, yoke and back gap regions wherein the yoke region is located between the pole tip and back gap regions;
forming a nonmagnetic electrically nonconductive write gap layer between the first and second pole piece layers in the pole tip region;
forming an insulation stack with at least one coil layer embedded therein between the first and second pole piece layers in the yoke region;
and
connecting the first and pole piece layers at said back gap region;
and making a read head including the steps of:
forming nonmagnetic electrically nonconductive first and second read gap layers;
forming a spin valve sensor between the first and second read gap layers;
forming the first and second read gap layers between the first shield layer and the first pole piece layer;
and a making of the spin valve sensor comprising the steps of:
forming a ferromagnetic pinned layer that has a magnetic moment;
forming a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
forming a free layer;
and
forming a nonmagnetic electrically conductive spacer layer located between the free layer and the pinned layer;
forming the spin valve sensor with top and bottom surfaces and first and second side surfaces which intersect the ABS;
forming first and second hard bias layers abutting the first and second side surfaces respectively of the spin valve sensor;
forming first and second lead layers connected to the spin valve sensor for conducting a sense current transversely therethrough;
forming the spin valve sensor with a transverse length between the first and second side surfaces which is divided into a track width region between first and second passive regions wherein the track width region is defined by a space between said first and second lead layers;
forming the free layer with first and second passive portions in the first and second passive regions which have first and second surfaces respectively;
forming first and second antiferromagnetic (AFM) layers exchange coupled to said first and second top surfaces for longitudinally biasing the first and second passive portions of the free layer.

19 more elements

Dependencies are inferred from the claim text.

Description3,818 words

Summary1,728 words

#1. Field of the Invention

#The present invention relates to a lead overlay spin valve sensor with antiferromagnetic layers in passive regions for stabilizing a free layer and, more particularly, to such sensors which are highly sensitive and stable even though they have a small track width.

#2. Description of the Related Art

Brief description of the drawings11 figures

#FIG. 1 is a plan view of a magnetic disk drive;

#FIG. 2 is an end view of a slider with a magnetic head of the disk drive as seen in plane 2—2 of FIG. 1;

#FIG. 3 is an elevation view of the magnetic disk drive wherein multiple disks and magnetic heads are employed;

Detailed description1,857 words

#Referring now to the drawings wherein like reference numerals designate like or similar parts throughout the several views, FIGS. 1-3 illustrate a magnetic disk drive 30. The drive 30 includes a spindle 32 that supports and rotates a magnetic disk 34. The spindle 32 is rotated by a spindle motor 36 that is controlled by a motor controller 38. A slider 42 has a combined read and write magnetic head 40 and is supported by a suspension 44 and actuator arm 46 that is rotatably positioned by an actuator 47. A plurality of disks, sliders and suspensions may be employed in a large capacity direct access storage device (DASD) as shown in FIG. 3. The suspension 44 and actuator arm 46 are moved by the actuator 47 to position the slider 42 so that the magnetic head 40 is in a transducing relationship with a surface of the magnetic disk 34. When the disk 34 is rotated by the spindle motor 36 the slider is supported on a thin (typically, 0.05 μm) cushion of air (air bearing) between the surface of the disk 34 and the air bearing surface (ABS) 48. The magnetic head 40 may then be employed for writing information to multiple circular tracks on the surface of the disk 34, as well as for reading information therefrom. Processing circuitry 50 exchanges signals, representing such information, with the head 40, provides spindle motor drive signals for rotating the magnetic disk 34, and provides control signals to the actuator for moving the slider to various tracks. In FIG. 4 the slider 42 is shown mounted to a suspension 44. The components described hereinabove may be mounted on a frame 54 of a housing 55, as shown in FIG. 3.

#FIG. 5 is an ABS view of the slider 42 and the magnetic head 40. The slider has a center rail 56 that supports the magnetic head 40, and side rails 58 and 60. The rails 56, 58 and 60 extend from a cross rail 62. With respect to rotation of the magnetic disk 34, the cross rail 62 is at a leading edge 64 of the slider and the magnetic head 40 is at a trailing edge 66 of the slider.

#FIG. 6 is a side cross-sectional elevation view of a piggyback magnetic head 40, which includes a write head portion 70 and a read head portion 72, the read head portion employing a dual spin valve sensor 74 of the present invention. FIG. 8 is an ABS view of FIG. 6. The spin valve sensor 74 is sandwiched between nonmagnetic electrically insulative first and second read gap layers 76 and 78, and the read gap layers are sandwiched between ferromagnetic first and second shield layers 80 and 82. In response to external magnetic fields, the resistance of the spin valve sensor 74 changes. A sense current Is conducted through the sensor causes these resistance changes to be manifested as potential changes. These potential changes are then processed as readback signals by the processing circuitry 50 shown in FIG. 3.

Facts

Application

09/814,135Filed 20 Mar 2001

Published

US 2002/0135953 A126 Sep 2002

Granted

21 Oct 2003

Term ended

4 Jan 2022

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 290 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification6 codes

G11B 5/3932
Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding: magnetic biasing films
B82Y 10/00
Nanotechnology for information processing, storage or transmission
G11B 5/3903
Using magneto-resistive devices or effects: using magnetic thin film layers or their effects, the films being part of integrated structures
G11B 5/399
Using magnetic thin film layers or their effects, the films being part of integrated structures: with intrinsic biasing, e.g. provided by…

Timeline

20 Mar 2001Application filedUS 09/814,135
20 Mar 2001Assigned to International Business Machines Corporationassignment of assignor's interest
26 Sep 2002PublishedUS 2002/0135953 A1
21 Oct 2003GrantedUS 6,636,397 B2
21 Sep 2005Assigned to Hitachi Global Storage Technologies Netherlands B.V.assignment of assignor's interest
4 Jan 2022Term endedEstimated, includes 290 days of adjustment

Lead overlay spin valve sensor with antiferromagnetic layers in passive regions for stabilizing a free layer

Life of this patent

Lead overlay spin valve sensor with antiferromagnetic layers in passive regions for stabilizing a free layer

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims25

Description3,818 words

Drawings

Classification6 codes

Life of this patent

Description3,818 words