Method for extended self-pinned layer for a current perpendicular to plane head
View Patent ↗A Giant Magneto-Resistive (GMR) sensor ( 900 ) having Current Perpendicular to Plane (CPP) structure is formed providing an extended first pinned layer ( 914 ) as compared to second pinned layer ( 912 ) and free layer ( 910 ). Increased magnetoresistance changes, increased pinning strength, increased thermal stability, and decreased susceptibility to Electro-Static Discharge (ESD) events is realized by maintaining equivalent current densities through free layer ( 910 ) and second pinned layer ( 912 ), while decreasing the relative current density through first pinned layer ( 914 ).
1. A method of forming a spin valve sensor, comprising:
forming a first pinned layer with a top surface, bottom surface and sides orthogonal to the top and bottom surface and having a first magnetic orientation and a first width;
forming a second pinned layer with sides orthogonal to the top and bottom surface of the first pinned layer and having a second magnetic orientation anti-parallel to the first magnetic orientation and a second width;
forming a sensing layer with sides orthogonal to the top and bottom surface of the first pinned layer and having a third width smaller than the first width; and
forming a spacer layer with sides orthogonal to the top and bottom surface of the first pinned layer and having a width equal to the second width;
wherein the third width is selected to coincide with a predetermined track width, the first width being selected to be wider than the predetermined track width.
2. The method according to claim 1 , further comprising forming a coupling layer disposed between the first and second pinned layers.
3. The method according to claim 2 , wherein the first and second pinned layers are formed with substantially equal thickness.
4. The method according to claim 3 , wherein forming the first and second pinned layers creates self-pinned magnetic orientations.
5. The method according to claim 3 , further comprising depositing an anti-ferromagnetic material (AFM) adjacent to the first pinned layer, wherein a thickness of the AFM creates exchange coupling between the AFM and the first pinned layer.
6. The method according to claim 1 , wherein forming the sensing layer includes:
forming a free layer having a third magnetic orientation orthogonal to the first and second magnetic orientations;
forming a bias layer in proximity to the free layer having a fourth magnetic orientation anti-parallel to the third magnetic orientation; and
forming an AFM layer adjacent to the bias layer, wherein exchange coupling between the AFM layer and the bias layer sets the fourth magnetic orientation.
7. The method according to claim 6 , wherein the bias layer is formed with a thickness greater than a thickness of the free layer.
8. The method according to claim 1 , wherein the second pinned layer is formed with a width substantially equal to the third width.
9. The method according to claim 8 , wherein insulating layers are disposed on both sides of the second pinned layer.
10. The method according to claim 1 , wherein the second pinned layer is formed with a width substantially equal to the first width.
11. The method according to claim 1 , wherein insulating layers are disposed on both sides of the sensing layer.