Spin valve sensor having ultra-thin freelayers including nickel-iron, ruthenium, and a cobalt-iron nanolayer

• US 6,826,021 B2
• Filed: 04/03/2002
• Issued: 11/30/2004
• Est. Priority Date: 04/03/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Pinarbasi, Mustafa
• Primary Examiner(s): Renner, Craig A.
• Application Number:
  US10/115,467
• Publication Number:
  US 20030189800A1
• Time in Patent Office: 972 Days
• Field of Search: 360/324.12, 360/314
• 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: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• 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 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures

Abstract

A spin valve (SV) sensor has a cap layer made of tantalum; a copper layer formed beneath the cap layer; and a unique freelayer structure. The freelayer structure includes a first layer made of nickel-iron, a second layer made of ruthenium, a third layer made of nickel-iron, a nanolayer made of cobalt-iron, and a spacer layer made of copper adjacent the nanolayer of cobalt-iron. The first layer of nickel-iron is no greater than each one of the third layer of nickel-iron and the nanolayer of cobalt-iron. The nanolayer has a thickness of no more than 30 Angstroms. The net freelayer thickness, determined based on subtracting a thickness of the first layer of nickel-iron from a sum of thicknesses of the third layer of nickel-iron and the nanolayer of cobalt-iron, is less than 50 Angstroms. Advantageously, this thin structure provides a high magnetoresistive coefficient and soft magnetic properties.

Claims

1. A spin valve (SV) sensor, comprising:

a cap layer made of tantalum (Ta);

a copper (Cu) layer formed beneath the cap layer;

a freelayer structure which includes;

a first layer made of nickel-iron (NiFe);

a second layer made of ruthenium (Ru);

a third layer made of nickel-iron (NiFe);

the second layer of Ru formed between the first and third layers of NiFe;

a nanolayer made of cobalt-iron (CoFe);

a spacer layer made of copper (Cu) adjacent the nanolayer of CoFe;

wherein the first layer of NiFe is no greater than each one of the third layer of NiFe and the nanolayer of CoFe;

wherein the nanolayer has a thickness that is no more than 30 Angstroms; and

wherein a net freelayer thickness of the SV sensor, determined based on subtracting a thickness of the first layer of NiFe from a sum of thicknesses of the third layer of NiFe and the nanolayer of CoFe, is less than 50 Angstroms.

2. The SV sensor of claim 1, wherein the first and the third layers of NiFe comprise Ni₈₃Fe₁₇.

3. The SV sensor of claim 1, wherein the nanolayer of CoFe comprises Co₉₀Fe₁₀.

4. The SV sensor of claim 1, wherein the freelayer structure provides for an increased magnetoresistive coefficient and decreased coercivity.

5. The SV sensor of claim 1, further comprising:

a first antiparallel (AP) pinned layer;

a second AP-pinned layer;

an antiparallel coupling (APC) layer disposed between the first and the second AP-pinned layers; and

a seed layer formed beneath the first and the second AP-pinned layers which includes a nickel-iron (NiFe) alloy.

6. A magnetic head, comprising:

a spin valve (SV) sensor which includes;

a cap layer made of tantalum (Ta);

a copper (Cu) layer formed beneath the cap layer;

a plurality of freelayers which include a first layer consisting of nickel-iron (Ni₈₃Fe₁₇), a second layer made of ruthenium (Ru), and a third layer consisting of nickel-iron (Ni₈₃Fe₁₇);

the second layer of Ru formed between the first and third layers of Ni₈₃Fe₁₇;

a nanolayer consisting of cobalt-iron (Co₉₀Fe₁₀); and

a spacer layer made of copper (Cu) which is adjacent the nanolayer of Co₉₀Fe₁₀,

wherein the first layer of Ni₈₃Fe₁₇ is no greater than each one of the third layer of Ni₈₃Fe₁₇ and the nanolayer of Co₉₀Fe₁₀;

wherein the nanolayer has a thickness that is no more than 30 Angstroms; and

wherein a net freelayer thickness of the SV, determined by subtracting a thickness of the first layer of Ni₈₃Fe₁₇ from a sum of thicknesses of the third layer of Ni₈₃Fe₁₇ and the nanolayer of Co₉₀Fe₁₀, is less than 50 Angstroms.

7. The magnetic head of claim 6, further comprising:

a first antiparallel (AP)-pinned layer;

a second AP-pinned layer; and

an antiparallel coupling (APC) layer disposed between the first and the second AP-pinned layers.

8. A disk drive, comprising:

a magnetic head with a spin valve (SV) sensor which includes;

a cap layer made of tantalum (Ta);

a copper (Cu) layer formed beneath the cap layer;

a plurality of freelayers which include a first layer made of nickel-iron (NiFe), a second layer made of ruthenium (Ru), and a third layer made of nickel-iron (NiFe);

the second layer of Ru formed between the first and third layers of NiFe;

a nanolayer made of cobalt-iron (CoFe);

a spacer layer made of copper (Cu);

wherein the first layer of NiFe is no greater than each one of the third layer of NiFe and the nanolayer of CoFe;

wherein the nanolayer has a thickness that is no more than 30 Angstroms; and

wherein a net freelayer thickness of the SV sensor, determined based on subtracting a thickness of the first layer of NiFe from a sum of thicknesses of the third layer of NiFe and the nanolayer of CoFe, is less than 50 Angstroms.

9. The disk drive of claim 8, wherein the first and the third layers of NiFe comprise Ni₈₃Fe₁₇.

10. The disk drive of claim 8, wherein the nanolayer of CoFe comprises Co₉₀Fe₁₀.

11. The disk drive of claim 8, wherein the freelayers and nanolayer provide for an increased magnetoresistive coefficient and decreased coercivity in the SV sensor.

12. The disk drive of claim 8, wherein the first and the third layers of NiFe consist of NiFe.

13. The disk drive of claim 8, further comprising:

a first antiparallel (AP)-pinned layer;

a second AP-pinned layer;

an antiparallel coupling (APC) layer disposed between the first and the second AP-pinned layers; and

a seed layer formed beneath the first and the second AP-pinned layers which includes a nickel-iron (NiFe) alloy.