Dual tunnel junction sensor antiferromagnetic layer between pinned layers

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;
• a read head including a tunnel junction sensor;
• the tunnel junction sensor including:
• first and second pinned layers wherein each pinned layer has a magnetic moment;
• an antiferrromagnetic pinning layer located between and exchange coupled to each of the first and second pinned layers for pinning the magnetic moments of the first and second pinned layers parallel with respect to each other and perpendicular to the ABS;
• nonmagnetic electrically insulative first and second barrier layers;
• the first and second pinned layers being located between the first and second barrier layers;
• first and second free layer structures;
• the first and second barrier layers being located between the first and second free layer structures;
• the first free layer structure being an antiparallel (AP) coupled structure which includes:
• first and second antiparallel (AP) coupled layers;
• and
• a first antiparallel coupling (APC) layer located between and interfacing each of the first and second AP coupled layers;
• the second free layer structure being an antiparallel (AP) coupled structure which includes:
• third and fourth antiparallel (AP) coupled layers;
• and
• a second antiparallel coupling (APC) layer located between and interfacing each of the third and fourth AP coupled layers.

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 tunnel junction sensor;
• the tunnel junction sensor including:
• first and second pinned layers wherein each pinned layer has a magnetic moment;
• an antiferrromagnetic pinning layer located between and exchange coupled to each of the first and second pinned layers for pinning the magnetic moments of the first and second pinned layers parallel with respect to each other and perpendicular to the ABS;
• electrically insulative first and second barrier layers;
• the first and second pinned layers being located between the first and second barrier layers;
• first and second free layer structures;
• the first and second barrier layers being located between the first and second free layer structures;
• the first free layer structure being an antiparallel (AP) coupled structure which includes:
• first and second antiparallel (AP) coupled layers;
• and
• a first antiparallel coupling (APC) layer located between and interfacing each of the first and second AP coupled layers;
• the second free layer structure being an antiparallel (AP) coupled structure which includes:
• third and fourth antiparallel (AP) coupled layers;
• and
• a second antiparallel coupling (APC ) layer located between and interfacing each of the third and fourth AP coupled layers;
• 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 first and second pinned layers wherein each pinned layer has a magnetic moment;
• forming an antiferrromagnetic pinning layer between and exchange coupled to each of the first and second pinned layers for pinning the magnetic moments of the first and second pinned layers parallel with respect to each other and perpendicular to the ABS;
• forming electrically insulative first and second barrier layers;
• forming the first and second pinned layers between the first and second barrier layers;
• forming first and second free layer structures;
• forming the first and second barrier layers between the first and second free layer structures;
• the first free layer structure being an antiparallel (AP) coupled structure which is made including the steps of:
• forming first and second antiparallel (AP) coupled layers;
• and
• forming a first antiparallel coupling (APC) layer located between and interfacing each of the first and second AP coupled layers;
• the second free layer structure being an antiparallel (AP) coupled structure which is made including the steps of:
• forming third and fourth antiparallel (AP) coupled layers;
• and
• forming a second antiparallel coupling (APC ) layer between and interfacing each of the third and fourth AP coupled layers.

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 which includes a tunnel junction sensor;
• making the tunnel junction sensor including the steps of:
• forming first and second pinned layers wherein each pinned layer has a magnetic moment;
• forming an antiferrromagnetic pinning layer between and exchange coupled to each of the first and second pinned layers for pinning the magnetic moments of the first and second pinned layers parallel with respect to each other and perpendicular to the ABS;
• forming electrically insulative first and second barrier layers;
• forming the first and second pinned layers between the first and second barrier layers;
• forming first and second free layer structures;
• forming the first and second barrier layers between the first and second free layer structures;
• the first free layer structure being an antiparallel (AP) coupled structure which is formed including the steps of:
• forming first and second antiparallel (AP) coupled layers;
• and
• forming a first antiparallel coupling (APC) layer between and interfacing each of the first and second AP coupled layers;
• the second free layer structure being an antiparallel (AP) coupled structure which is formed including the steps of:
• forming third and fourth antiparallel (AP) coupled layers;
• and
• forming a second antiparallel coupling (APC) layer between and interfacing each of the third and fourth AP coupled layers.