Magnetic head having CPP sensor with improved biasing for free magnetic layer
View Patent ↗A magnetic head for a hard disk drive having a CPP read head sensor that includes a layered sensor stack including a free magnetic layer and hard bias elements that are disposed on the sides of the free magnetic layer to provide a biasing magnetization for the free magnetic layer. To increase the coercivity of the hard bias elements, and thereby improve the biasing of the magnetization of the free magnetic layer, the ratio (t/H) of the thickness t to the height H of the hard bias elements is fabricated to be within the range of from approximately 1 to approximately 1/15.
1. A magnetic head, comprising:
a CPP read sensor including a plurality of sensor layers, wherein said sensor layers are formed with an air bearing surface (ABS), side edges and a back edge that defines a sensor stripe height SH between the ABS and said back edge;
hard bias elements being disposed proximate said side edges, said hard bias elements having a height H and a thickness t, wherein the ratio of t/H is from approximately 1 to approximately 1/15;
an insulating layer extending around a corner of each of the hard bias elements and along a bottom and side of the hard bias element closest the side edges and defining the corner; and
a magnetic shield formed directly on the hard bias elements.
2. A magnetic head as described in claim 1 wherein t is within the range of from approximately 5 nm to approximately 60 mm.
3. A magnetic head as described in claim 1 wherein H is within the range of approximately SH to approximately 3 SH.
4. A magnetic head as described in claim 3 , wherein SH is within the range of from approximately 10 nm to approximately 100 mm.
5. A magnetic head as described in claim 1 wherein H is within the range of from approximately 20 nm to approximately 300 nm.
6. A hard disk drive, comprising:
a rotatable hard disk;
a magnetic head as recited in claim 1 , said magnetic head being disposed for reading data from said hard disk.
7. 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 plurality of sensor layers, wherein said sensor layers are formed with an air bearing surface (ABS), side edges and a back edge that defines a sensor stripe height SH between the ABS and said back edge;
hard bias elements being disposed proximate said side edges, said hard bias elements having a height H and a thickness t, wherein the ratio of t/H is from approximately 1 to approximately 1/15;
an insulating layer extending around a corner of each of the hard bias elements and along a bottom and side of the hard bias element closest the side edges and defining the corner; and
a magnetic shield formed directly on the hard bias elements.
8. A hard disk drive as described in claim 7 wherein t is within the range of from approximately 5 nm to approximately 60 nm.
9. A hard disk drive as described in claim 7 wherein H is within the range of approximately SH to approximately 3 SH.
10. A hard disk drive as described in claim 9 , wherein SH is within the range of from approximately 10 nm to approximately 100 nm.
11. A hard disk drive as described in claim 7 wherein H is within the range of from approximately 20 nm to approximately 300 nm.