Thermally stable oxidized bias layer structure for magnetoresistive magnetic head for a hard disk drive
View Patent ↗The magnetic head of the present invention includes a magnetoresistive read head element in which a magnetic bias layer is deposited across the surface of the wafer above the free magnetic layer. Central portions of the biasing layer that correspond to the read head track width are oxidized to essentially remove the magnetic moment of the bias layer material in those central locations. An oxygen diffusion barrier layer is then deposited upon the oxidized central portions of the biasing layer to prevent diffusion or migration of oxygen from the oxidized central regions of the biasing layer. An insulation layer, a second magnetic shield layer and further structures of the magnetic head are subsequently fabricated.
1. A magnetic head including a read head element, comprising:
a pinned magnetic layer;
a free magnetic layer having a central portion thereof having a free magnetization therewithin;
a magnetic bias layer, including a central portion thereof that is disposed across said central portion of said free magnetic layer;
said central portion of said bias layer being comprised of a material having an approximately zero magnetic moment;
a pair of electrical leads being disposed above said bias layer and on opposite sides of said central portion of said bias layer;
a barrier layer being disposed across said central portion of said bias layer and upon said electrical leads, wherein said barrier layer is not disposed between said electrical leads except in said locations of across said central portion of said bias layer and upon said electrical leads.
2. A magnetic head as described in claim 1 wherein said central portion of said bias layer is comprised of an oxidized material, and said barrier layer is comprised of a material that is a barrier to oxygen diffusion from said central portion of said bias layer.
3. A magnetic head as described in claim 2 , further including a thin spacer layer that is disposed upon said free magnetic layer, wherein said bias layer is disposed upon said thin spacer layer and said barrier layer is deposed upon said bias layer.
4. A magnetic head as described in claim 3 wherein said barrier layer is comprised of a material that has low electrical conductivity.
5. A magnetic head as described in claim 4 wherein said barrier layer is comprised of Ru or Rh.
6. A magnetic head as described in claim 5 wherein said barrier layer is comprised of Ru having a thickness of from approximately 5 Å to approximately 40 Å.
7. A magnetic head as described in claim 6 wherein said barrier layer has a thickness of approximately 20 Å.
8. A magnetic head as described in claim 3 wherein said thin spacer layer is comprised of a material that is a barrier to oxygen diffusion.
9. A magnetic head as described in claim 8 wherein said thin spacer layer is comprised of Ru.
10. A hard disk drive including a magnetic head including a read head element, comprising:
a pinned magnetic layer;
a free magnetic layer having a central portion thereof having a free magnetization therewithin;
a magnetic bias layer, including a central portion thereof that is disposed across said central portion of said free magnetic layer;
said central portion of said bias layer being comprised of a material having an approximately zero magnetic moment;
a pair of electrical leads being disposed above said bias layer and on opposite sides of said central portion of said bias layer;
a barrier layer being disposed across said central portion of said bias layer and upon said electrical leads, wherein said barrier layer is not disposed between said electrical leads except in said locations of across said central portion of said bias layer and upon said electrical leads.
11. A magnetic head as described in claim 10 wherein said central portion of said bias layer is comprised of an oxidized material, and said barrier layer is comprised of a material that is a barrier to oxygen diffusion from said central portion of said bias layer.
12. A magnetic head as described in claim 11 , further including a thin spacer layer that is disposed upon said free magnetic layer, wherein said bias layer is disposed upon said thin spacer layer and said barrier layer is deposed upon said bias layer.
13. A magnetic head as described in claim 12 wherein said barrier layer is comprised of a material that has low electrical conductivity.
14. A magnetic head as described in claim 13 wherein said barrier layer is comprised of Ru or Rh.
15. A magnetic head as described in claim 14 wherein said barrier layer is comprised of Ru having a thickness of from approximately 5 Å to approximately 40 Å.
16. A magnetic head as described in claim 15 wherein said barrier layer has a thickness of approximately 20 Å.
17. A magnetic head as described in claim 12 wherein said thin spacer layer is comprised of a material that is a barrier to oxygen diffusion.
18. A magnetic head as described in claim 17 wherein said thin spacer layer is comprised of Ru.
19. A method for fabricating a magnetic head, comprising:
fabricating a free magnetic layer;
fabricating a magnetic bias layer across said free magnetic layer;
fabricating electrical leads above portions of said bias layer;
oxidizing a central portion of said bias layer;
depositing an oxygen diffusion barrier layer upon said oxidized central portion of said bias layer and upon said electrical leads; and
removing portions of said barrier layer that are deposited at locations other than upon said electrical leads and upon said central portions of said bias layer.
20. A method for fabricating a magnetic head as described in claim 19 wherein said barrier layer is comprised of Ru or Rh.
21. A method for fabricating a magnetic head as described in claim 20 wherein said barrier layer is comprised of Ru and has a thickness of from approximately 5 Å to approximately 40 Å.
22. A method for fabricating a magnetic head as described in claim 21 wherein said barrier layer is formed with a thickness of approximately 20 Å.