Magnetoresistive device with laminate insertion layer in the free layer

• US 9,831,419 B2
• Filed: 07/13/2015
• Issued: 11/28/2017
• Est. Priority Date: 07/13/2015
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Freitag, James, Gao, Zheng
• Primary Examiner(s): YUSHINA, GALINA G
• Application Number:
  US14/797,759
• Publication Number:
  US 20170018703A1
• Time in Patent Office: 869 Days
• CPC Class Codes: G11B 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/3948 the sensitive elements being active read-out elements
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A magneto-resistive (MR) device and process for making the MR device are disclosed. The MR device has a pinned layer, a spacer layer proximate to the pinned layer, and a free layer proximate to the spacer layer. The free layer comprises a first magnetic layer proximate to the spacer layer, the first magnetic layer having a positive magnetostriction, a laminate magnetic insertion layer proximate to the first magnetic layer, and a second magnetic layer proximate to the magnetic insertion layer, the second magnetic layer having a negative magnetostriction. The laminate magnetic insertion layer has a first magnetic sublayer and a first non-magnetic sublayer proximate to the first magnetic sublayer. With the disclosed laminate magnetic insertion layer, the free layer has a low overall magnetostriction and results in a MR device with a high MR ratio.

Claims

1. A magneto-resistive (MR) device, comprising:

a pinned layer;

a spacer layer proximate to the pinned layer; and

a free layer proximate to the spacer layer, wherein the free layer comprises;

a first magnetic layer proximate to the spacer layer, the first magnetic layer having a positive magnetostriction,

a magnetic insertion layer proximate to the first magnetic layer, the magnetic insertion layer comprising a first insertion layer unit, the first insertion layer unit comprising a first magnetic sublayer and a first non-magnetic sublayer proximate to the first magnetic sublayer, and

a second magnetic layer proximate to the magnetic insertion layer, the second magnetic layer having a negative magnetostriction.

2. The MR device of claim 1, wherein the first magnetic sublayer is proximate to the first magnetic layer.

3. The MR device of claim 1, wherein the magnetic insertion layer further comprises a second magnetic sublayer proximate to the first non-magnetic sublayer.

4. The MR device of claim 1, wherein the magnetic insertion layer further comprises one or more additional insertion layer units, wherein each individual insertion layer unit of the one or more additional insertion layer units comprises a magnetic sublayer and a non-magnetic sublayer, and wherein each of the one or more additional insertion layer units is proximate to another insertion layer unit and oriented identically to the first insertion layer unit.

5. The MR device of claim 4, wherein a material of the magnetic sublayer of at least one of the one or more additional insertion layer units is identical to a material of the first magnetic sublayer, and a material of the non-magnetic sublayer of the at least one of the one or more additional insertion layer units is identical to a material of the first non-magnetic sublayer.

6. The MR device of claim 5, wherein a thickness of the at least one of the one or more additional insertion layer units is substantially equal to a thickness of the first insertion layer unit.

7. The MR device of claim 4, further comprising a second magnetic sublayer proximate to a last insertion layer unit, the last insertion layer unit being a one of the one or more additional insertion layer units that is furthest away from the first insertion layer unit.

8. The MR device of claim 7, wherein the first magnetic sublayer is proximate to the first magnetic layer, and the second magnetic sublayer is proximate to the second magnetic layer.

9. The MR device of claim 1, wherein a thickness of the magnetic insertion layer is less than twelve Angstroms.

10. The MR device of claim 1, wherein a thickness of the first magnetic sublayer is less than three times a thickness of the first non-magnetic sublayer.

11. The MR device of claim 1, wherein the first magnetic sublayer comprises iron (Fe), cobalt (Co), or alloys thereof.

12. The MR device of claim 1, wherein the first non-magnetic sublayer comprises tantalum (Ta), hafnium (Hf), tungsten (W), vanadium (V), niobium (Nb), zirconium (Zr), titanium (Ti), molybdenum (Mo), or chromium (Cr).

13. The MR device of claim 1, wherein the spacer layer comprises magnesium oxide (MgO).

14. The MR device of claim 1, wherein the spacer layer comprises copper (Cu), silver (Ag), Ag—

Sn alloys, aluminum oxide, or titanium dioxide.

15. The MR device of claim 1, wherein the first magnetic layer comprises cobalt (Co), iron (Fe), boron (B), or any combination of these.

16. The MR device of claim 1, wherein the second magnetic layer comprises nickel (Ni), iron (Fe), or a combination of these.

17. A sensor comprising the MR device of claim 1.

18. A memory comprising the MR device of claim 1.

19. A disk drive comprising the MR device of claim 1.

20. A process for fabricating the MR device of claim 1, the process comprising:

forming the pinned layer;

forming the spacer layer proximate to the pinned layer; and

forming the free layer proximate to the spacer layer, wherein forming the free layer comprises;

forming the first magnetic layer proximate to the spacer layer, the first magnetic layer having the positive magnetostriction,

forming the magnetic insertion layer proximate to the first magnetic layer, the magnetic insertion layer comprising the first insertion layer unit, the first insertion layer unit comprising the first magnetic sublayer and the first non-magnetic sublayer proximate to the first magnetic sublayer, and

forming the second magnetic layer proximate to the magnetic insertion layer, the second magnetic layer having the negative magnetostriction.

21. The process recited in claim 20, wherein forming comprises sputtering.

22. A MR device manufactured according to the process of claim 20.