Tunnel valve sensor having a pinned layer structure with an iron oxide (Fe3O4) layer

A magnetic head assembly having an air bearing surface (ABS), comprising:

• a write head including:
• ferromagnetic first and second pole piece layers that have a yoke portion located between a pole tip portion and a back gap portion;
• a nonmagnetic write gap layer located between the pole tip portions of the first and second pole piece layers;
• an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
• and
• the first and second pole piece layers being connected at their back gap portions;
• and
• a read head including:
• a first shield layer;
• a tunnel junction sensor located between the first shield layer and the first pole piece layer;
• the tunnel junction sensor including:
• a ferromagnetic pinned layer structure that has a magnetic moment;
• an antiferromagnetic pinning layer structure exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• a ferromagnetic free layer structure which has a magnetic moment;
• and
• a nonmagnetic electrically insulative barrier layer located between the free layer structure and the pinned layer structure;
• the free layer structure having a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer;
• and
• the pinned layer structure having a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer.

A magnetic disk drive including at least one magnetic head assembly that has an a write head, a read head and an air bearing surface (ABS) comprising:

• the write head including:
• ferromagnetic first and second pole piece layers that have a yoke portion located between a pole tip portion and a back gap portion;
• a nonmagnetic write gap layer located between the pole tip portions of the first and second pole piece layers;
• an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
• and
• the first and second pole piece layers being connected at their back gap portions;
• and
• the read head including:
• a first shield layer;
• a tunnel junction sensor located between the first shield layer and the first pole piece layer;
• the tunnel junction sensor including:
• a ferromagnetic pinned layer structure that has a magnetic moment;
• an antiferromagnetic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• a ferromagnetic free layer structure which has a magnetic moment;
• a nonmagnetic electrically insulative barrier layer located between the free layer structure and the pinned layer structure;
• the free layer structure having a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer;
• and
• the pinned layer structure having a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer;
• a housing;
• a magnetic disk rotatably supported in the housing;
• a support mounted in the housing for supporting the magnetic head assembly with said ABS facing the magnetic disk so that the magnetic head assembly is in a transducing relationship with the magnetic disk;
• a spindle motor for rotating the magnetic disk;
• an actuator positioning means connected to the support for moving the magnetic head assembly to multiple positions with respect to said magnetic disk;
• and
• a processor connected to the magnetic head assembly, to the spindle motor and to the actuator for exchanging signals with the magnetic head assembly, for controlling movement of the magnetic disk and for controlling the position of the magnetic head assembly.

A method of making a magnetic read head which has an air bearing surface (ABS), comprising the steps of:

• making a tunnel junction sensor including the steps of:
• forming a ferromagnetic pinned layer structure with a magnetic moment;
• forming an antiferromagnetic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• forming a ferromagnetic free layer structure with a magnetic moment;
• forming a nonmagnetic electrically insulative barrier layer between the free layer structure and the pinned layer structure;
• forming the free layer structure with a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer;
• and
• forming the pinned layer structure with a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer.

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 gap regions wherein the yoke region is located between the pole tip and back gap regions;
• forming 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 a first shield layer;
• and
• forming a tunnel junction sensor between the first shield layer and the first pole piece layer;
• a making of the tunnel junction sensor comprising the steps of:
• forming a ferromagnetic pinned layer structure with a magnetic moment;
• forming an antiferromagnetic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• forming a ferromagnetic free layer structure with a magnetic moment;
• forming a nonmagnetic electrically insulative barrier layer located between the free layer structure and the pinned layer structure;
• forming the free layer structure with a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer;
• and
• forming the pinned layer structure with a cobalt iron (CoFe) layer and an iron oxide (Fe3O4) layer.