MAGNETORESISTIVE DEVICE AND METHOD FOR FORMING THE SAME

• US 20140110804A1
• Filed: 10/18/2013
• Published: 04/24/2014
• Est. Priority Date: 10/18/2012
• Status: Abandoned Application

• Current Assignee: Agency For Science Technology and Research
• Original Assignee: Agency For Science Technology and Research
• Inventors: Han, Guchang, Wang, Jacob ChenChen, Tran, Michael, Eason, Kwaku
• Application Number:
  US14/057,198
• Publication Number:
  US 20140110804A1
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details

Abstract

According to embodiments of the present invention, a magnetoresistive device is provided. The magnetoresistive device includes a free magnetic layer structure having a variable magnetization orientation, and a synthetic antiferromagnetic layer structure including at least three ferromagnetic layers arranged one over the other and antiferromagnetically coupled, each ferromagnetic layer having a fixed magnetization orientation, wherein the free magnetic layer structure and the synthetic antiferromagnetic layer structure are arranged one over the other. According to further embodiments of the present invention, a method for forming a magnetoresistive device is also provided.

Claims

1. A magnetoresistive device comprising:

a free magnetic layer structure having a variable magnetization orientation; and

a synthetic antiferromagnetic layer structure comprising at least three ferromagnetic layers arranged one over the other and antiferromagnetically coupled, each ferromagnetic layer having a fixed magnetization orientation,

wherein the free magnetic layer structure and the synthetic antiferromagnetic layer structure are arranged one over the other.

2. The magnetoresistive device as claimed in claim 1, wherein an effective magnetic thickness of the synthetic antiferromagnetic layer structure is at least substantially zero.

3. The magnetoresistive device as claimed in claim 1, wherein, for the at least three ferromagnetic layers arranged one over the other, a ferromagnetic layer that is arranged proximal to the free magnetic layer structure has a magnetic thickness that is smaller than the respective magnetic thicknesses of the other ferromagnetic layers.

4. The magnetoresistive device as claimed in claim 1, wherein the synthetic antiferromagnetic layer structure further comprises

at least two antiferromagnetic coupling layers,

wherein a respective antiferromagnetic coupling layer of the at least two antiferromagnetic coupling layers is arranged between respective adjacent ferromagnetic layers of the at least three ferromagnetic layers.

5. The magnetoresistive device as claimed in claim 1, further comprising an antiferromagnetic layer configured to pin the synthetic antiferromagnetic layer structure.

6. The magnetoresistive device as claimed in claim 1, further comprising a spacer layer between the free magnetic layer structure and the synthetic antiferromagnetic layer structure.

7. The magnetoresistive device as claimed in claim 1, further comprising a cancellation layer structure configured to provide a field to compensate for a field originating from the synthetic antiferromagnetic layer structure.

8. The magnetoresistive device as claimed in claim 7, wherein the synthetic antiferromagnetic layer structure and the cancellation layer structure are arranged on opposite sides of the free magnetic layer structure.

9. The magnetoresistive device as claimed in claim 7, wherein a magnetization orientation of the cancellation layer structure is anti-parallel to the magnetization orientation of the ferromagnetic layer of the at least three ferromagnetic layers that is arranged proximal to the free magnetic layer structure.

10. The magnetoresistive device as claimed in claim 7, wherein the cancellation layer structure comprises a synthetic antiferromagnetic layer structure, the synthetic antiferomagnetic layer comprising at least two antiferromagnetically coupled ferromagnetic layers.

11. The magnetoresistive device as claimed in claim 7, further comprising a non-magnetic spacer layer between the cancellation layer structure and the free magnetic layer structure.

12. The magnetoresistive device as claimed in claim 1, further comprising a seed layer structure, wherein the free magnetic layer structure and the synthetic antiferromagnetic layer structure are arranged over the seed layer.

13. The magnetoresistive device as claimed in claim 1, further comprising a cap layer structure arranged over the free magnetic layer structure and the synthetic antiferromagnetic layer structure.

14. The magnetoresistive device as claimed in claim 1, wherein the free magnetic layer structure comprises a single magnetic layer or a bilayer structure or a multilayer structure comprising a plurality of bilayer structures.

15. The magnetoresistive device as claimed in claim 1, wherein the ferromagnetic layer that is arranged proximal to the free magnetic layer structure comprises a single magnetic layer or a bilayer structure or a multilayer structure comprising a plurality of bilayer structures.

16. The magnetoresistive device as claimed in claim 1, wherein each ferromagnetic layer has a thickness that is less than about 20 nm.

17. The magnetoresistive device as claimed in claim 1, wherein the synthetic antiferromagnetic layer structure comprises one or more further ferromagnetic layers.

18. A method for forming a magnetoresistive device, the method comprising:

forming a free magnetic layer structure having a variable magnetization orientation; and

forming a synthetic antiferromagnetic layer structure comprising at least three ferromagnetic layers arranged one over the other and antiferromagnetically coupled, each ferromagnetic layer having a fixed magnetization orientation,

wherein the free magnetic layer structure and the synthetic antiferromagnetic layer structure are arranged one over the other.

19. The method as claimed in claim 18, wherein an effective magnetic thickness of the synthetic antiferromagnetic layer structure is at least substantially zero.

20. The method as claimed in claim 18, further comprising forming a cancellation layer structure, the cancellation layer structure configured to provide a field for compensating a field originating from the synthetic antiferromagnetic layer structure.