Method of manufacturing a magnetoresistive sensor with a thin antiferromagnetic layer for pinning antiparallel coupled tabs
View Patent ↗A manufacturing method for a spin valve sensor with a thin antiferromagnetic (AFM) layer exchange coupled to a self-pinned antiparallel coupled bias layer in the lead overlap regions is provided. The spin valve sensor comprises forming a ferromagnetic bias layer antiparallel coupled to a free layer in first and second passive regions where first and second lead layers overlap the spin valve sensor layers and forming a thin AFM layer exchange coupled to the bias layer to provide a pinning field to the bias layer. A cap layer is deposited over the thin AFM layer.
1. A method of making a spin valve (SV) sensor having first and second passive regions and a central track width region transversely disposed between said first and second passive regions, the method comprising the steps of:
depositing sequentially a pinned layer, a spacer layer and a free layer;
depositing ferromagnetic material to form a ferromagnetic bias layer antiparallel coupled to the free layer by an antiparallel coupling layer sandwiched between the free layer and the bias layer;
depositing an antiferromagnetic material to form an antiferromagnetic (AFM) layer adjacent to said ferromagnetic bias layer, said AFM layer exchange coupled to the ferromagnetic bias layer to provide a pinning field to the bias layer;
depositing a cap layer over the AFM layer;
depositing first and second lead layers over the cap layer, said first and second lead layers overlapping the first and second passive regions, respectively, central wherein the track width region between the first and second passive regions is defined by a space between the first and second lead layers;
removing the cap layer in the central track width region between the first and second lead layers;
converting the antiferromagnetic material of the AFM layer and the ferromagnetic material of the central bias layer in the ferromagnetic track width region into a nonmagnetic oxide layer; and
setting the AFM layer so that the pinning field to the ferromagnetic bias layer is directed in a predetermined direction.
2. The method as recited in claim 1 wherein the step of removing the cap layer in the central track width region uses a sputter etch and reactive ion etch process.
3. The method as recited in claim 1 wherein the step of converting the ferromagnetic material of the bias layer in the track width region into a nonmagnetic oxide layer uses a sputter etch process with an oxygen containing gas.
4. The method as recited in claim 1 wherein said pinning field is directed in a longitudinal direction parallel to an air bearing surface.
5. The method as recited in claim 1 wherein said pinning field is directed in a transverse direction perpendicular to an air bearing surface.
6. The method as recited in claim 1 wherein said pinning field is directed in a canted direction intermediate between a direction parallel to an air bearing surface and a direction perpendicular to the air bearing surface.