Spin valve head with diffusion barrier

Details Spin valve head with diffusion barrier Spin valve head with diffusion barrier

1998-07-31

2001-02-27

Renner, Craig A. (Department: 2652)

Dynamic magnetic information storage or retrieval

Head

Magnetoresistive reproducing head

C360S324110

Reexamination Certificate

active

06195240

ABSTRACT:

TECHNICAL FIELD
The present invention relates to the field of spin valve read heads for reading data from rotating magnetic media, and more specifically to a spin valve head having a diffusion barrier to prevent degradation of spin valve performance during thermal treatment of the spin valve head. The predominant current usage of the present inventive spin valve head with diffusion barrier is in high capacity fixed disk data drive mechanisms wherein a read head having high sensitivity is desired.
BACKGROUND ART
Spin valve (“SV”) heads (sometimes referred to as giant magneto resistive heads or “GMR” heads) are very attractive for use as high density recording magneto resistive (“MR”) rip heads because of their high readback output voltages, linear response, and symmetrical read sensitivity profiles.
FIG. 1
shows an air bearing surface view of a prior art SV sensor
10
comprising end regions
12
and
14
separated by a central region
16
. A free layer (free ferromagnetic layer)
18
is separated from a pinned layer (pinned ferromagnetic layer)
20
by a non-magnetic, electrically-conducting spacer layer
22
(typically, primarily copper). The magnetization of the pinned layer
20
is fixed through exchange coupling with an antiferromagnetic (AFM) layer
24
. The magnetization of the free layer
18
, however, is free to rotate in the presence of an external field. Free layer
18
, spacer layer
22
, pinned layer
20
and the AFM layer
24
are all formed in the central region
16
. Hard bias layers
26
and
28
formed in the end regions
12
and
14
, respectively, provide longitudinal bias for the MR free layer
18
. Leads
30
and
32
formed over hard bias layers
26
and
28
, respectively, provide electrical connections for the flow of the sensing current Is, from a current source
34
to the SV sensor
10
. A signal detector
40
which is electrically connected to the leads
30
and
32
senses the change in resistance of the SV sensor
10
due to changes induced by the external magnetic field (e.g., the field generated by a when a field transition on a disk is moved past the SV sensor
10
. In the example of
FIG. 1
, a cap
42
is optionally provided.
During the manufacturing of a read/write head for magnetic recording media, the write head may be formed on top of the SV sensor
10
. During the manufacture of the write head, and during some of the processes involved in manufacturing the SV sensor
10
, itself, high temperature processes have inevitably been involved. (Examples are the photoresist baking of the write head, the annealing of the AFM layer
24
material which is required for some materials, and resetting of the pinned layer
20
.) At these temperatures, the grain boundaries of adjacent materials tend to become aligned, notably at the junction of the spacer
22
and the free layer
18
and/or at the boundary of the spacer
22
and the pinned layer
20
. In this condition, it is very easy for diffusion between such layers to occur. This results in a degradation of the output signal amplitude produced by the SV sensor
10
.
Clearly, it would be desirable to prevent the degradation caused to longer term thermal treatment of the spin valve head during the manufacturing process. However, to the inventor's knowledge, no prior art construction or process has effectively and sufficiently reduced the reduction of spin valve output amplitude caused by such thermal treatment.
DISCLOSURE OF INVENTION
Accordingly, it is an object of the present invention to provide a spin valve which retains high amplitude output even after thermal treatment.
It is still another object of the present invention to provide a spin valve head which is sufficiently sensitive to accurately detect minor flux changes.
It is yet another object of the present invention to provide a spin valve which will withstand thermal treatments during manufacture with a minimum of degradation.
It is still another object of the present invention to provide a spin valve which will can be it readily manufactured.
Briefly, the preferred embodiment of the present invention is a spin valve which has a very thin layer of amorphous metal between the spacer layer and the free layer, thereby removing the grain boundaries between these layers and thus greatly reducing diffusion between these layers during the thermal processes necessary to the manufacture of the spin valve. Thereby, degradation of amplitude output of the spin valve which has normally been caused by these thermal processes is minimized.
An advantage of the present invention is that a spin valve will have a high output amplitude.
A further advantage of the present invention is that thermal processes during manufacture can be tolerated without degradation of amplitude.
Yet another advantage of the present invention is that read head sensitivity is increased. Still another advantage of the present invention is that it is made easier to manufacture spin valve read heads without causing degradation of the finished product.


REFERENCES:
patent: 5484491 (1996-01-01), Iwasaki et al.
patent: 5657191 (1997-08-01), Yuan
patent: 5701223 (1997-12-01), Fontana, Jr. et al.
patent: 5717550 (1998-02-01), Nepela et al.
patent: 5896252 (1999-04-01), Kanai
patent: 5909345 (1999-06-01), Kawawake et al.
patent: 5955211 (1999-09-01), Maeda et al.
patent: 5966012 (1999-10-01), Parkin
patent: 6034847 (2000-03-01), Komuro et al.
patent: 6046892 (2000-04-01), Aoshima et al.
patent: 6088195 (2000-07-01), Kamiguchi et al.
patent: 197 01 509 (1997-07-01), None
patent: 0 758 783 (1997-02-01), None
patent: 9-199768 (1997-07-01), None

Affiliated with

Also associated with

Rating

Spin valve head with diffusion barrier does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Spin valve head with diffusion barrier, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spin valve head with diffusion barrier will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2560420