Stabilization structure for CPP GMR/TV
View Patent ↗A magnetic head has a read sensor which includes at least one primary pinned layer, a barrier layer, and a free layer. An in-stack biasing structure having net magnetic moment near zero, notated as dM=0, is constructed above the free layer. This in-stack biasing structure acts to stabilize the free layer by exchange coupling.
1. A magnetic head comprising:
a read sensor which is of Current Perpendicular to the Plane (CPP) configuration including:
at least one primary pinned layer;
a barrier layer;
a free layer;
an in-stack biasing structure having net magnetic moment which is substantially equal to zero, which acts to stabilize said free layer by exchange coupling.
2. The magnetic head of claim 1 , wherein:
said in-stack biasing structure includes paired layers of opposite magnetic orientation which are separated by a spacer layer, such that the net magnetic moment of said paired layers is substantially zero.
3. The magnetic head of claim 2 , wherein:
said net magnetic moment substantially equal to zero corresponds to a difference in thickness of said paired layers of opposite magnetic orientation which is less than 5×10 −10 meters.
4. The magnetic head of claim 1 , wherein:
said in-stack biasing structure includes a self-pinned layer pair.
5. The magnetic head of claim 1 , wherein:
said at least one primary pinned layer includes a pair of primary pinned layers, separated by a spacer layer.
6. The magnetic head of claim 5 , further comprising:
at least one layer of AFM material which acts to pin said pair of primary pinned layers.
7. The magnetic head of claim 5 , wherein:
said pair of primary pinned layers are self-pinned layers.
8. A disk drive comprising:
at least one hard disk;
at least, one magnetic head adapted to fly over said hard disk for writing data on said hard disk, and having an air bearing surface, said magnetic head including:
a read sensor which is of Current Perpendicular to the Plane (CPP) configuration including:
at least one primary pinned layer;
a baffler layer;
a free layer;
an in-stack biasing structure having net magnetic moment which is substantially equal to zero, which acts to stabilize said free layer by exchange coupling.
9. The disk drive of claim 8 , wherein:
said in-stack biasing structure includes paired layers of opposite magnetic orientation which are separated by a spacer layer, such that the net magnetic moment of said paired layers is substantially zero.
10. The disk drive of claim 9 , wherein:
said net magnetic moment substantially equal to zero corresponds to a difference in thickness of said paired layers of opposite magnetic orientation which is less than 5×10 −10 meters.
11. The disk drive of claim 8 , wherein:
said in-stack biasing structure includes a self-pinned layer pair.
12. The disk drive of claim 8 , wherein:
said at least one primary pinned layer includes a pair of primary pinned layers, separated by a spacer layer.
13. The disk drive of claim 12 , further comprising:
at least one layer of AFM material which acts to pin said pair of primary pinned layers.
14. The disk drive of claim 12 , wherein:
said pair of primary pinned layers are self-pinned layers.