Method for manufacturing a spin valve having an enhanced free layer
View Patent ↗A spin valve sensor is provided with a negative ferromagnetic coupling field −H FC for properly biasing a free layer and a spin filter layer is employed between the free layer and a capping layer for increasing the magnetoresistive coefficient dr/R of the spin valve sensor. A top portion of the free layer is oxidized for improving the negative ferromagnetic coupling field −H FC when the spin filter layer is employed for increasing the magnetoresistive coefficient dr/R.
1. A method of making a magnetic read head which has an air bearing surface (ABS), comprising the steps of:
making a spin valve sensor including the steps of:
forming a ferromagnetic pinned layer that has a magnetic moment;
forming a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
forming a free layer;
forming a nonmagnetic conductive spacer layer between the free layer and the pinned layer;
forming a capping layer with the free layer being located between the spacer layer and the capping layer;
forming the free layer with an oxidized film portion and an unoxidized film portion with the oxidized film portion being located between the unoxidized film portion and the capping layer;
forming a copper layer between the oxidized film portion of the free layer and the capping layer;
forming nonmagnetic nonconductive first and second read gap layers;
forming the spin valve sensor between the first and second read gap layers;
forming ferromagnetic first and second shield layers; and
forming the first and second read gap layers between the first and second shield layers,
wherein the unoxidixed film portion of the free layer is formed as a nickel iron film and the oxidized film portion of the free layer is formed as a nickel iron oxide film.
2. The method as claimed in claim 1 further including forming the copper layer fully oxidized or with an oxidized film portion and an unoxidized film portion.
3. The method as claimed in claim 1 wherein the pinning layer is formed of platinum manganese.
4. The method as claimed in claim 3 wherein the making of the spin valve sensor further includes the steps of:
forming first and second seed layers with the first seed layer composed of nickel manganese oxide and the second seed layer composed of tantalum with the second seed layer being located between the first seed layer and the pinning layer; and
forming the first read gap layer of aluminum oxide.
5. The method as claimed in claim 4 wherein the copper layer is formed 4-10 Å thick.
6. The method as claimed in claim 5 wherein the capping layer is formed of tantalum.
7. The method as claimed in claim 6 wherein a forming of the pinned layer comprises the steps of:
forming ferromagnetic first and second antiparallel (AP) pinned films with the first AP film interfacing the pinning layer; and
forming an antiparallel (AP) coupling film between the first and second AP films.
8. A method of making a magnetic read head which has an air bearing surface ABS, comprising the steps of:
making a spin valve sensor including the steps of:
forming a ferromagnetic pinned layer that has a magnetic moment;
forming a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
forming a free layer;
forming a nonmagnetic conductive spacer layer between the free layer and the pinned layer;
forming a capping layer with the free layer being located between the spacer layer and the capping layer;
forming the free layer with an oxidized film portion and an unoxidized film portion with the oxidized film portion being located between the unoxidized film portion and the capping layer; and
forming a copper layer between the oxidized film portion of the free layer and the capping layer;
forming nonmagnetic nonconductive first and second read gap layers;
forming the spin valve sensor between the first and second read gap layers;
forming ferromagnetic first and second shield layers; and
forming the first and second read gap layers between the first and second shield layers,
wherein the unoxidized film portion of the free layer is formed as a cobalt iron film and the oxidized film portion of the free layer is formed as a cobalt iron oxide film, and
wherein the free layer is further formed with a nickel iron film with the cobalt iron film being located between the spacer layer and the nickel iron film.
9. The method as claimed in claim 8 wherein the free layer further includes forming a nickel iron oxide film between the nickel iron film and the cobalt iron film.
10. A method of making magnetic head assembly that has an air bearing surface (ABS), comprising the steps of:
making a write head including the steps of:
forming ferromagnetic first and second pole piece layers in pole tip, yoke and back and regions wherein the yoke region is located between the pole tip and back gap regionforming a nonmagnetic nonconductive write gap layer between the first and second pole piece layers in the pole tip region;
forming an insulation stack with at least one coil layer embedded therein between the first and second pole piece layers in the yoke region; and
connecting the first and pole piece layers at said back gap region; and making a read head including the steps of:
forming nonmagnetic nonconductive first and second read gap layers:
forming a spin valve sensor between the first and second read gap layers;
forming the first and second read gap layers between the first shield layer and the first pole piece layer; and a making of the spin valve sensor comprising the steps of:
forming a ferromagnetic pinned layer that has a magnetic moment;
forming a pinning layer exchange coupled to the pinned layer for pinning the magnetic moment of the pinned layer;
forming a free layer;
forming a nonmagnetic conductive spacer layer between the free layer and the pinned layer;
forming a capping layer with the free layer being located between the spacer layer and the capping layer;
forming the free layer with an oxidized film portion and an unoxidized film portion with the oxidized film portion being located between the unoxidized film portion and the capping layer; and
forming a copper layer between the oxidized film portion of the free layer and the capping layer,
wherein the unoxidized film portion of the free layer is formed as a nickel iron film and the oxidized film portion of the free layer is formed as a nickel iron oxide film.
11. The method as claimed in claim 10 further including forming the copper layer fully oxidized or with an oxidized film portion and an unoxidized film portion.
12. The method as claimed in claim 10 wherein the pinning layer is formed of platinum manganese.
13. The method as claimed in claim 12 wherein the making of the spin valve sensor further includes the steps of:
forming first and second seed layers with the first seed layer composed of nickel manganese oxide and the second seed layer composed of tantalum with the second seed layer being located between the first seed layer and the pinning layer; and
forming the first read gap layer of aluminum oxide.
14. The method as claimed in claim 13 wherein the copper layer is formed 4-10 A thick.
15. The method as claimed in claim 14 wherein the capping layer is formed of tantalum.
16. The method as claimed in claim 15 wherein a forming of the pinned layer comprises the steps of:
forming ferromagnetic first and second antiparallel (AP) pinned films with the first Ap film interfacing the pinned layer; and forming an antiparallel (AP) coupling film between the first and second AP films.