Tunnel magnetoresistance read head with narrow shield-to-shield spacing
View Patent ↗A tunnel magnetoresistance (TMR) read sensor having a tabbed AFM layer and an extended pinned layer and methods for making the same are provided. The TMR read sensor has an AFM layer recessed from the air bearing surface, providing a reduced shield-to-shield distance.
1. A read sensor comprising:
a shield layer intersecting an air bearing surface plane;
an antiferromagnetic layer disposed over the shield layer;
an antiferromagnet exchange biased first pinned layer disposed over the antiferromagnetic layer, the antiferromagnetic layer and antiferromagnet exchange biased first pinned layer being recessed from the air bearing surface plane;
a second pinned layer disposed over and magnetically coupled to the antiferromagnet exchange biased first pinned layer, the second pinned layer intersecting the air bearing surface plane;
a barrier layer disposed over the second pinned layer and intersecting the air bearing surface plane;
a free layer disposed over the barrier layer and intersecting the air bearing surface plane; and
a capping layer disposed over the free layer and intersecting the air bearing surface plane.
2. The read sensor of claim 1 , wherein:
the free layer extends to a stripe height distance from the air bearing surface plane;
the antiferromagnetic layer and the antiferromagnet exchange biased first pinned layer are recessed from the air bearing surface plane by at least the stripe height distance; and
the second pinned layer extends beyond the free layer back edge to approximately the same length as the antiferromagnet exchange biased first pinned layer.
3. The read sensor of claim 1 , wherein the antiferromagnetic layer and the antiferromagnet exchange biased first pinned layer are recessed from the air bearing surface plane by between 10 nm and 500 nm.
4. The read sensor of claim 1 , wherein the antiferromagnet exchange biased first pinned layer comprises a soft magnetic stitching layer disposed over the antiferromagnetic layer.
5. The read sensor of claim 4 , wherein the antiferromagnetic layer comprises IrMn, PtMn, PdPtMn, NiMn, RhMn, or RhRuMn.
6. The read sensor of claim 4 , wherein the soft magnetic stitching layer comprises CoFe, NiFe, or CoNiFe.
7. The read sensor of claim 4 , wherein the soft magnetic stitching layer comprises a multilayer comprising:
a first soft ferromagnetic layer;
a second soft ferromagnetic layer disposed over the first ferromagnetic layer; and
a non-magnetic layer disposed between the first soft ferromagnetic layer and the second soft ferromagnetic layer;
the non-magnetic layer having a thickness approximately equal to a first or a second oscillatory peak of the exchange coupling between the first soft ferromagnetic layer and the second soft ferromagnetic layer; and
the non-magnetic layer comprising Ru, Cr, Ag, or Au.