Multilayer spin valve magneto-resistive effect magnetic head with free magnetic layer including two sublayers and magnetic disk drive including same

• US 5,896,252 A
• Filed: 05/02/1997
• Issued: 04/20/1999
• Est. Priority Date: 08/11/1995
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kanai, Hitoshi
• Primary Examiner(s): Renner, Craig A.
• Application Number:
  US08/850,796
• Time in Patent Office: 718 Days
• Field of Search: 360/113, 324/252, 338/32 R
• US Class Current: 360/324.12
• 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 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures

Abstract

A spin valve magnetoresistive effect magnetic head has a free magnetic layer having two sublayers composed of a CoFe sublayer and an NiFe sublayer. Alternatively, the two sublayers may be composed of a CoFe layer and an NiFe based alloy layer. The magnetic head further includes a nonmagnetic layer stacked on the CoFe layer, a pinned magnetic layer stacked on the nonmagnetic layer and an antiferromagnetic layer for fixing a magnetization direction of the pinned magnetic layer according to an exchange coupling between the pinned magnetic layer and the antiferromagnetic layer.

Claims

1. A spin valve magnetoresistive effect magnetic head comprising:

a free magnetic layer consisting of a CoFe sublayer and an NiFe sublayer;

an underlying layer made of tantalum beneath and in direct physical contact with the free magnetic layer;

a nonmagnetic layer stacked on the CoFe sublayer;

a pinned magnetic layer stacked on the nonmagnetic layer;

an antiferromagnetic layer for fixing a magnetization direction of the pinned magnetic layer according to an exchange coupling between the pinned magnetic layer and the antiferromagnetic layer; and

a pair of electrode terminals for passing a current through the free magnetic layer, the nonmagnetic layer, the pinned magnetic layer and the antiferromagnetic layer;

wherein a composition ratio of the CoFe sublayer is 95 to 85 wt % of Co and 5 to 15 wt % of Fe.

2. A spin valve magnetoresistive effect magnetic head according to claim 1, wherein a composition ratio of the CoFe sublayer is 90 wt % of Co and 10 wt % of Fe.

3. A spin valve magnetoresistive effect magnetic head according to claim 1, wherein a film thickness of the CoFe sublayer is in a range of 10 to 100 Å

.

4. A spin valve magnetoresistive effect magnetic head according to claim 1, wherein a film thickness of the NiFe sublayer is in a range of 10 to 100 Å

.

5. A spin valve magnetoresistive effect magnetic head according to claim 1, wherein the pinned magnetic layer is formed of CoFe.

6. A spin valve magnetoresistive effect magnetic head according to claim 1, wherein the nonmagnetic layer is formed of Cu.

7. A spin valve magnetoresistive effect magnetic head according to claim 1, wherein the underlying layer is directly below the free magnetic layer.

8. A spin valve magnetoresistive effect magnetic head comprising:

a free magnetic layer consisting of a CoFe sublayer and an NiFe based alloy sublayer;

an under layer made of tantalum beneath and in direct physical contact with the free magnetic layer,

a nonmagnetic layer stacked on the CoFe sublayer;

a pinned magnetic layer stacked on the nonmagnetic layer;

an antiferromagnetic layer for fixing a magnetization direction of the pinned magnetic layer according to an exchange coupling between the pinned magnetic layer and the antiferromagnetic layer; and

a pair of electrode terminals for flowing a current through the free magnetic layer, the nonmagnetic layer, the pinned magnetic layer and the antiferromagnetic layer;

wherein a composition ratio of the CoFe sublayer is 95 to 85 wt % of Co and 5 to 15 wt % of Fe.

9. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein a composition ratio of the CoFe sublayer is 90 wt % of Co and 10 wt % of Fe.

10. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein a film thickness of the CoFe sublayer is in a range of 10 to 100 Å

.

11. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein the NiFe based alloy sublayer is made of NiFeCr, NiFeNb, or NiFeRh.

12. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein a film thickness of the NiFe based alloy sublayer is in a range of 10 to 100 Å

.

13. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein the pinned magnetic layer is formed of CoFe.

14. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein the nonmagnetic layer is formed of Cu.

15. A spin valve magnetoresistive effect magnetic head according to claim 8, wherein the under layer is directly below the free magnetic layer.

16. A magnetic disk drive comprising a magnetic recording medium and a spin valve magnetoresistive effect magnetic head for writing in and reading out information in the magnetic recording medium, wherein the spin valve magnetoresistive effect magnetic head is comprised of:

a free magnetic layer consisting of two sublayers where one sublayer is a CoFe sublayer and the other sublayer is an NiFe sublayer or an NiFe based alloy sublayer;

an under layer made of tantalum beneath and in direct physical contact with the free magnetic layer,

a nonmagnetic layer stacked on the CoFe sublayer;

a pinned magnetic layer stacked on the nonmagnetic layer;

an antiferromagnetic layer for fixing a magnetization direction of the pinned magnetic layer according to an exchange coupling between the pinned magnetic layer and the antiferromagnetic layer; and

a pair of electrode terminals for flowing a current through the free magnetic layer, the nonmagnetic layer, the pinned magnetic layer and the antiferromagnetic layer;

wherein a composition ratio of the CoFe sublayer is 95 to 85 wt % of Co and 5 to 15 wt % of Fe.

17. A magnetic disk drive according to claim 16, wherein the under layer is directly below the free magnetic layer.