Magnetoresistive sensor with sub-layering of pinned layers

A method of fabricating a magnetic head that has a magnetoresistive read sensor, comprising:

• depositing a seed layer above a lower shield;
• depositing a free layer above the seed layer;
• depositing a barrier layer above the free layer;
• depositing a sub-second pinned layer above the barrier layer;
• depositing above the sub-second pinned layer a separation layer that is different from the sub-second pinned layer and a ferromagnetic second pinned layer;
• depositing the ferromagnetic second pinned layer above the separation layer;
• depositing an antiparallel-coupling layer above the second pinned layer;
• depositing a ferromagnetic first pinned layer above the antiparallel-coupling layer;
• depositing an antiferromagnetic pinning layer above the first pinned layer;
• and
• depositing a capping layer above the antiferromagnetic pinning layer.

A hard disk drive, comprising:

• a hard disk;
• an actuator arm;
• a slider disposed upon a distal end of the actual arm and positionable over the hard disk;
• and
• a read head disposed on the slider, the read head comprising:
• a lower ferromagnetic shield;
• a tunneling magnetoresistance (TMR) read sensor stack, comprising:
• a sensing ferromagnetic free layer deposited on the lower ferromagnetic shield;
• an electrically insulating nonmagnetic barrier layer deposited on the free layer;
• a ferromagnetic sub-second pinned layer deposited on the barrier layer;
• a tantalum containing separation layer;
• a ferromagnetic second pinned layer deposited on the separation layer;
• an antiparallel-coupling layer deposited on the second pinned layer;
• a ferromagnetic first pinned layer deposited on the antiparallel-coupling layer;
• and
• an antiferromagnetic pinning layer deposited on the first pinned layer;
• and
• an upper ferromagnetic shield deposited on the TMR stack.