Current perpendicular-to-the-plane magnetoresistance read head

• US 6,704,175 B2
• Filed: 07/13/2001
• Issued: 03/09/2004
• Est. Priority Date: 03/28/2001
• Status: Expired due to Fees

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Araki, Satoru, Li, Shuxiang
• Primary Examiner(s): OMETZ, DAVID LOUIS
• Application Number:
  US09/903,698
• Publication Number:
  US 20020159201A1
• Time in Patent Office: 970 Days
• Field of Search: 360/324.1, 360/324.11, 360/324.12, 360/324.2
• US Class Current: 360/324.11
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G11B 2005/0008 Magnetic conditionning of heads, e.g. biasing
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3932 Magnetic biasing films

Abstract

A magnetoresistive (MR) head including, for example, a spin valve (SV) MR element having a sense current passing through the SV in a current-perpendicular-to-the-plane (CPP) mode. A free layer of the SV is transversely biased by a magnetostatic coupling field from an in-stack transverse bias layer. The transverse bias layer is separated from the free layer by a nonmagnetic high resistive spacer layer, which can cause strong spin memory loss and also provide a longitudinal biasing to the free layer of the SV. An out of stack longitudinal bias arrangement may alternatively be provided to impart a longitudinal bias to the free layer. The SV MR element comprises a MR promoting (MRP) layer either within in or adjacent to the free layer 90 or the pinned layer 110 This MR head structure provides enhanced linearity of the response to the magnetic field being sensed.

Claims

1. A current perpendicular-to-the-plane magnetoresistance (CPP-MR) read head having a stacked structure, comprising:

a spin valve arrangement; and

a transverse bias means for providing a transverse bias to the spin valve arrangement,

wherein said transverse bias means is an in-stack anti-parallel bias (AP-bias) layer, and said in-stack AP-bias layer includes first and second ferromagnetic layers having magnetization directions arranged to be opposite from each other.

2. The CPP-MR read head of claim 1, further comprising:

a longitudinal bias means for providing a longitudinal bias to the spin valve arrangement.

3. The CPP-MR read head of claim 2, wherein said longitudinal bias means is an in-stack conductive spacer layer.

4. A current perpendicular-to-the-plane magnetoresistance (CPP-MR) read head having a stacked structure, comprising:

a spin valve arrangement;

a transverse bias means for providing a transverse bias to the spin valve arrangement; and

a longitudinal bias means for providing a longitudinal bias to the spin valve arrangement,

wherein said longitudinal bias means is an in-stack conductive spacer layer, and said in-stack conductive spacer layer is composed of a material that causes a strong spin memory loss for conduction electrons passing through the CPP-MR read head.

5. A magnetoresistance read head having a stacked structure, comprising:

a fixed layer having a magnetization direction pinned in a particular direction;

a free layer having a magnetization that is free to rotate in varying directions; and

an in-stack transverse bias arrangement providing a transverse bias to the free layer,

wherein said in-stack transverse bias arrangement is an anti-parallel bias (AP-bias) layer, and said AP-bias layer includes first and second ferromagnetic layers having magnetization directions arranged to be opposite from each other.

6. The read head of claim 5, further comprising:

a longitudinal bias arrangement providing a longitudinal bias to the free layer.

7. The read head of claim 6, wherein said longitudinal bias arrangement is an in-stack conductive spacer layer.

8. The read head of claim 5, further comprising:

a magnetoresistance (MR) promoting layer composed of high resistivity materials and situated adjacent to the fixed layer.

9. The read head of claim 8, further comprising:

a second magnetoresistance (MR) promoting layer composed of high resistivity materials and situated adjacent to the free layer.

10. The read head of claim 5, further comprising:

a magnetoresistance (MR) promoting layer composed of high resistivity materials and situated within the fixed layer.

11. The read head of claim 10, further comprising:

a second magnetoresistance (MR) promoting layer composed of high resistivity materials and situated within the free layer.

12. The read head of claim 5, wherein the free layer is wider than the pinned layer in a direction of a track to be read by the read head.

13. A magnetoresistance read head having a stacked structure, comprising:

a fixed layer having a magnetization direction pinned in a particular direction;

a free layer having a magnetization that is free to rotate in varying directions;

an in-stack transverse bias arrangement providing a transverse bias to the free layer; and

a longitudinal bias arrangement providing a longitudinal bias to the free layer,

wherein said longitudinal bias arrangement is an in-stack conductive spacer layer, and said in-stack conductive spacer layer is composed of materials that cause a strong spin memory loss for conduction electrons passing through the read head.

14. A method of magnetically biasing a current perpendicular-to-the-plane magnetoresistance (CPP-MR) read head having a stacked structure, comprising:

generating a current in a spin valve structure in the CPP-MR read head;

magnetically biasing a free layer of the spin valve structure; and

magnetically counter-biasing the free layer with an in-stack transverse bias arrangement,

wherein the in-stack transverse bias arrangement used in the step of magnetically counter-biasing a free layer is an anti-parallel bias (AP-bias) layer, and the AP-bias layer used in the step of magnetically counter-biasing a free layer includes first and second ferromagnetic layers having magnetization directions arranged to be opposite from each other.

15. The method of claim 14, further comprising:

magnetically biasing the free layer of the spin valve structure in a longitudinal direction with a longitudinal bias arrangement.

16. The method of claim 15, wherein the longitudinal bias arrangement used in the step of magnetically biasing the free layer is an in-stack conductive spacer layer.

17. The method of claim 14, further comprising:

providing at least one magnetoresistance (MR) promoting layer composed of high resistivity materials within the stacked structure of the read head.

18. A method of magnetically biasing a current perpendicular-to-the-plane magnetoresistance (CPP-MR) read head having a stacked structure, comprising:

generating a current in a spin valve structure in the CPP-MR read head;

magnetically biasing a free layer of the spin valve structure;

magnetically counter-biasing the free layer with an in-stack transverse bias arrangement; and

magnetically biasing the free layer of the spin valve structure in a longitudinal direction with a longitudinal bias arrangement,

wherein the longitudinal bias arrangement used in the step of magnetically biasing the free layer is an in-stack conductive spacer layer, and the in-stack conductive spacer layer is composed of a material that causes a strong spin memory loss for conduction electrons passing through the CPP-MR read head.

19. A method of magnetically biasing a current perpendicular-to-the-plane magnetoresistance (CPP-MR) read head having a stacked structure, comprising:

generating a current in a spin valve structure in the CPP-MR read head;

magnetically biasing a free layer of the spin valve structure; and

magnetically counter-biasing the free layer with an in-stack transverse bias arrangement,

wherein the in-stack transverse bias arrangement used in the step of magnetically counter-biasing a free layer is an anti-parallel bias (AP-bias) layer, and the AP-bias layer used in the step of magnetically counter-biasing a free layer includes first and second ferromagnetic layers having magnetization directions arranged to be opposite from each other, and

wherein the first and second ferromagnetic layers of the AP-bias layer have respective saturation magnetic moments that differ from each other, so that an APnet value of the AP-bias layer is not zero.