Magnetic head having CPP sensor with improved stabilization of the magnetization of the pinned magnetic layer
A magnetic head having a CPP read head sensor that includes a layered sensor stack including an antiferromagnetic (AFM) layer, a pinned magnetic layer, and a free magnetic layer. The pinned magnetic layer is comprised of a high, positive magnetostriction material and has a thickness t and a height (H), such that the ratio (t/H) of the thickness t to the height H of the pinned magnetic layer is fabricated to be within the range of from approximately 1/10 to approximately 1/500. Ion milling is conducted at a grazing angle to the surface of the layer upon which the pinned magnetic layer is fabricated, where the ion beam is oriented in the direction of the desired magnetization of the pinned magnetic layer.
1. A magnetic head, comprising:
a CPP read sensor including a pinned magnetic layer and a free magnetic layer, wherein said sensor is formed with an air bearing surface (ABS);
wherein a back wall of said free magnetic layer defines a sensor stripe height SH between the ABS and said back wall of said free magnetic layer;
wherein said pinned magnetic layer has a back wall that defines a height H of said pinned magnetic layer between said ABS and said back wall of said pinned magnetic layer, and wherein H is greater than SH; and wherein said pinned magnetic layer is formed with a thickness t where the ratio of t/H is from approximately 1/10 to approximately 1/500; and
wherein said pinned magnetic layer is comprised of a high positive magnetostriction material that is disposed upon a conditioned surface that has been ion milled,
wherein said conditioned surface has physical characteristics of being ion milled in a same direction as a direction of magnetization of the pinned magnetic layer at a grazing angle of from approximately 45° to approximately 80° from normal to said conditioned surface.
2. A magnetic head as described in claim 1 wherein the ratio of t/H is within the range of from approximately 1/100 to approximately 1/400.
3. A magnetic head as described in claim 1 wherein t is within the range of from approximately 1 nm to approximately 6 nm.
4. A magnetic head as described in claim 1 wherein H is within the range of from approximately 30 nm to approximately 3000 nm.
5. A magnetic head as described in claim 1 wherein said pinned magnetic layer is comprised of at least one layer of CoFe, where the Fe composition is in the range of from 40 at. % to 50 at. %.
6. A magnetic head as described in claim 1 wherein said sensor is a GMR sensor.
7. A magnetic head as described in claim 1 wherein said sensor is a TMR sensor.
8. A magnetic head as described in claim 1 wherein said sensor further includes an AFM layer that is formed with a height H.
9. A magnetic head as described in claim 8 wherein said surface is a top surface of said AFM layer.
10. A magnetic head as described in claim 1 wherein said sensor further includes an underlayer that is formed with a height H.
11. A magnetic head as described in claim 10 wherein said conditioned surface is a top surface of said underlayer.
12. A hard disk drive, comprising:
a rotatable hard disk;
a magnetic head being disposed for reading data from said hard disk, said magnetic head, including:
a CPP read sensor including a pinned magnetic layer, and a free magnetic layer, wherein said sensor is formed with an air bearing surface (ABS);
wherein a back wall of said free magnetic layer defines a sensor stripe height SH between the ABS and said back wall of said free magnetic layer;
wherein said pinned magnetic layer has a back wall that defines a height H of said pinned magnetic layer between said ABS and said back wall of said pinned magnetic layer, and wherein H is greater than SH; and wherein said pinned magnetic layer is formed with a thickness t where the ratio of t/H is from approximately 1/10 to approximately 1/500; and
wherein said pinned magnetic layer is comprised of a high positive magnetostriction material that is disposed upon a conditioned surface that has been ion milled wherein said conditioned surface has physical characteristics of being ion milled in a same direction as a direction of magnetization of said pinned magnetic layer at a grazing angle of from approximately 45° to approximately 80° from normal to said conditioned surface.
13. A hard disk drive as described in claim 12 wherein the ratio of t/H is within the range of from approximately 1/100 to approximately 1/400.
14. A hard disk drive as described in claim 12 wherein t is within the range of from approximately 1 nm to approximately 6 nm.
15. A hard disk drive as described in claim 12 wherein H is within the range of from approximately 30 nm to approximately 3000 nm.
16. A hard disk drive as described in claim 12 wherein said pinned magnetic layer is comprised of at least one layer of CoFe, where the Fe composition is in the range of from 40 at. % to 50 at. %.
17. A hard disk drive as described in claim 12 wherein said sensor is a GMR sensor.
18. A hard disk drive as described in claim 12 wherein said sensor is a TM sensor.
19. A hard disk drive as described in claim 12 wherein said sensor further includes an AFM layer that is formed with a height H.
20. A hard disk drive as described in claim 19 wherein said surface is a top surface of said AFM layer.
21. A hard disk drive as described in claim 12 wherein said sensor further includes an underlayer that is formed with a height H.
22. A hard disk drive as described in claim 21 wherein said conditioned surface is a top surface of said underlayer.