Magnetic sensor with a recessed reference layer assembly and a front shield
A magnetic sensor has at least a free sub-stack, a reference sub-stack and a front shield. The free sub-stack has a magnetization direction substantially perpendicular to the planar orientation of the layer and extends to an air bearing surface. The reference sub-stack has a magnetization direction substantially perpendicular to the magnetization direction of the free sub-stack. The reference sub-stack is recessed from the air bearing surface and a front shield is positioned between the reference sub-stack and the air bearing surface.
1. A magnetic sensor comprising:
a magnetoresistive stack positioned between to and bottom shields on an air bearing surface (ABS), the magnetoresistive stack comprises at least a spacer layer disposed between reference and magnetically free laminations, the reference lamination continuously extending to a rear plane, distal the ABS, and separated from the ABS by a front shield having an angled back wall with respect to the ABS, the magnetically free lamination continuously extends from the ABS to the rear plane.
2. The magnetic sensor of claim 1 and further comprising:
an insulating layer positioned between the front shield and the reference and magnetically free laminations, respectively.
3. The magnetic sensor of claim 1 and further comprising:
first and second side shields positioned on opposite sides of the reference lamination.
4. The magnetic sensor of claim 3 , wherein the first and second side shields are in magnetic contact with the front shield.
5. The magnetic sensor of claim 4 , wherein the from shield, is in magnetic contact with at least one of the top shield and a bottom shield.
6. The magnetic sensor of claim 5 and further comprising:
an insulating layer positioned between the magnetoresistive stack and the from shield, first side shield, and second side shield.
7. The magnetic sensor of claim 3 , wherein first and second side shields comprise a soft magnetic material.
8. The magnetic sensor of claim 3 , wherein the top shield, bottom shield and first and second side shields comprise magnetically soft insulating material.
9. The magnetic sensor of claim 1 , wherein the bottom shield is coupled to the magnetically free lamination and connected to an insulating layer such that sense current flow is confined to a region proximate the ABS.
10. The magnetic sensor of claim 1 , wherein the back wall of the front shield facilitates increased magnetic flux flow from the media confronting surface into the magnetoresistive stack.
11. The magnetic sensor of claim 1 , wherein the reference lamination comprises a nonmagnetic layer, magnetic pinning layer, and antiferromagnetic layer.
12. The magnetic sensor of claim 1 , wherein the front shield separates the spacer layer from the ABS.
13. The magnetic sensor of claim 1 , wherein the magnetically free lamination has a first ferromagnetic freelayer directly coupled to a second ferromagnetic freelayer.
14. The magnetic sensor of claim 13 wherein the first freelayer comprises a material Chosen from the group of: GdFe, GdCoFe, TbCo, TbCoFe, other Co alloys, other Fe alloys, Pt alloys, Pd alloys, and bilayers of Co and Pt, Fe and Pt, CoCr and Pt, CoFe and Pt, Co and Pd, Fe and Pd, CoCr and Pd, and CoFe and Pd.
15. The magnetic sensor of claim 13 wherein the second freelayer comprises a material chosen from the group of CoFeB, Co, Fe, Ni, CoFeB alloys, other Co alloys, other Fe alloys, Ni alloys, CoB, CoRu, CoRh, and CoPt.
16. The magnetic sensor of claim 13 , wherein the second ferromagnetic freelayer is positioned between the first ferromagnetic freelayer and the spacer layer.
17. The magnetic sensor of claim 16 , wherein the second ferromagnetic freelayer is recessed from the ABS by an insulating layer.
18. An apparatus comprising:
magnetoresistive stack configured with an air bearing surface (ABS) and having a spacer layer disposed between a reference lamination a magnetically free lamination, the reference lamination continuously extending to a rear plane, distal the ABS, and separated from the ABS by a front shield having an angled back wall with respect to the ABS, the magnetically free lamination continuously extending from the ABS to the rear plane, the magnetically free lamination having a first freelayer extending from the rear plane to the ABS and a second freelayer extending from the rear plane to a front plane, the front plane distal the ABS.
19. A data reader comprising:
a magnetoresistive stack having a spacer layer disposed between a reference lamination and a magnetically free lamination, the reference lamination continuously extending from a rear plane to a front plane, the magnetically free lamination continuously extending from the rear plane to an air bearing surface (ABS), the front plane separated from the ABS by a front shield having an angled back wall with respect to the ABS.
20. The data reader of claim 19 , wherein the magnetically free lamination comprises first and second free layers contactingly adjacent each other.