Magnetic sensing device with reduced shield-to-shield spacing

Patent metadata

Field	Value
Publication number	US-9442171-B2
Application number	US-97166408-A
Country	US
Kind code	B2
Filing date	Jan 9, 2008
Priority date	Jan 9, 2008
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A magnetic sensor assembly includes first and second shields each comprised of a magnetic material. The first and second shields define a physical shield-to-shield spacing. A sensor stack is disposed between the first and second shields and includes a seed layer adjacent the first shield, a cap layer adjacent the second shield, and a magnetic sensor between the seed layer and the cap layer. At least a portion of the seed layer and/or the cap layer comprises a magnetic material to provide an effective shield-to-shield spacing of the magnetic sensor assembly that is less than the physical shield-to-shield spacing.

First claim

The invention claimed is:

1. A magnetic sensor assembly comprising:
first and second shields comprising a magnetic material, wherein a distance between the first and second shields defines a physical shield-to-shield spacing; and
a sensor stack positioned between the first and second shields, the sensor stack including a first seed layer, first cap layer, and magnetic sensor; wherein the first seed layer and first cap layer comprise a magnetic material such that an effective shield-to-shield spacing of the magnetic sensor assembly does not include the first seed layer and first cap layer.

2. The magnetic sensor assembly of claim 1 , wherein the first seed layer comprises a material selected from the group consisting of NiFeNb, NiFeTa, NiFeRh, CoZrTa, CoZrNb, CoZrNd, CoFeB, CoFeTa, CoFeZr, CoFeRh, CoFe, CoCr, or Ni >70% Cr <30% .

3. The magnetic sensor assembly of claim 1 , wherein a crystalline structure of the first seed layer matches a crystalline structure of the first shield.

4. The magnetic sensor assembly of claim 1 , wherein a crystalline structure of the first cap layer matches a crystalline structure of the second shield.

5. The magnetic sensor assembly of claim 1 , wherein the first seed layer comprises an amorphous material.

6. The magnetic sensor assembly of claim 1 , wherein the first seed layer has a thickness between about 10 Å and 1,000 Å.

7. The magnetic sensor assembly of claim 6 , wherein the first seed layer is 50 Å thick.

8. The magnetic sensor assembly of claim 1 , further comprising:
a nonmagnetic second seed layer adjacent the first seed layer.

9. The magnetic sensor assembly of claim 8 , wherein the second seed layer comprises either Ru or Cu.

10. The magnetic sensor assembly of claim 9 , wherein the first seed layer comprises CoZrTa.

11. The magnetic sensor assembly of claim 10 , wherein the first seed layer is 30 Å thick and the second seed layer is 30 Å thick.

12. The magnetic sensor assembly of claim 1 , further comprising:
a nonmagnetic second cap layer adjacent the first cap layer.

13. The magnetic sensor assembly of claim 12 , wherein the second cap layer comprises Ta.

14. The magnetic sensor assembly of claim 13 , wherein the first cap layer comprises a material selected from the group consisting of NiFeNb, NiFeTa, NiFeRh, CoZrTa, CoZrNb, CoZrNd, CoFeB, CoFeTa, CoFeZr, CoFeRh, CoFe, CoCr, or Ni >70% Cr <30% .

15. A magnetic sensor assembly comprising:
first and second shields comprising a magnetic material, wherein a distance between the first and second shields defines a physical shield-to-shield spacing; and
a sensor stack positioned between the first and second shields, the sensor stack including a first seed layer comprising an amorphous material, first cap layer, and magnetic sensor; wherein the first seed layer and first cap layer comprise a magnetic material such that an effective shield-to-shield spacing of the magnetic sensor assembly does not include the first seed layer and first cap layer.

16. A magnetic sensor assembly comprising:
first and second shields comprising a magnetic material, wherein a distance between the first and second shields defines a physical shield-to-shield spacing; and
a sensor stack positioned between the first and second shields, the sensor stack including a first seed layer, first cap layer, and magnetic sensor; wherein the first seed layer and first cap layer comprise a magnetic material such that an effective shield-to-shield spacing of the magnetic sensor assembly does not include the first seed layer and first cap layer, and wherein a crystalline structure of the first cap layer matches a crystalline structure of the second shield.

Assignees

• Singleton Eric W
• He Qing
• Yi Jae-Young
• Johnson Matt
• Gao Zheng
• Dimitrov Dimitar V
• Xue Song S
• Seagate Technology Llc

Inventors

• Singleton Eric W
• He Qing
• Yi Jae-Young
• Johnson Matt
• Gao Zheng
• Dimitrov Dimitar V
• Xue Song S

Classifications

• G01R33/093 Primary

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• G11B5/3912 Primary

  Arrangements in which the active read-out elements are transducing in association with active magnetic shields, e.g. magnetically coupled shields (G11B5/3916 takes precedence) · CPC title

• G11B5/398

  Specially shaped layers · CPC title

• B82Y25/00

  Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance · CPC title

• G01R33/0076

  Protection, e.g. with housings against stray fields · CPC title