Spin valve sensor with magnetic and nonmagnetic layers for improving asymmetry and softness of a free layer structure

A magnetic head assembly 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;
• the read head including:
• a spin valve sensor;
• first and second hard bias and lead layers connected to the valve sensor;
• nonmagnetic nonconductive first and second read gap layers;
• the spin valve sensor and the first and second hard bias and lead layers being located between the first and second read gap layers;
• a ferromagnetic first shield layer;
• and
• the first and second gap layers being located between the first shield layer and the first pole piece layer;
• the spin valve sensor including:
• a ferromagnetic free layer structure that has a magnetic moment;
• a ferromagnetic pinned layer structure that has a magnetic moment;
• a nonmagnetic conductive spacer layer located between the free layer structure and the pinned layer structure;
• an antiferromagnetic metallic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• a conductive magnetic keeper layer for providing at least a partial magnetic flux closure for said pinned layer structure;
• and
• a nonmagnetic conductive first sense current field producing layer located between the keeper layer and the free layer structure for at least partially counterbalancing sense current fields from layers on an opposite side of the free layer structure.

A magnetic disk drive 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 spin valve sensor;
• first and second hard bias and lead layers connected the spin valve sensor;
• nonmagnetic nonconductive first and second read gap layers;
• the spin valve sensor being located between the first and second read gap layers;
• a ferromagnetic first shield layer;
• and
• the first and second read gap layers being located between the first shield layer and the first pole piece layer;
• the spin valve sensor including:
• a ferromagnetic free layer structure that has a magnetic moment;
• a ferromagnetic pinned layer structure that has a magnetic moment;
• a nonmagnetic conductive spacer layer located between the free layer structure and the pinned layer structure;
• an antiferromagnetic metallic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• a conductive magnetic keeper layer for providing at least a partial magnetic flux closure for said pinned layer structure;
• and
• a nonmagnetic conductive first sense current field producing layer located between the keeper layer and the free layer structure for at least partially counterbalancing sense current fields from layers on an opposite side of the free layer structure;
• and
• 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 to multiple positions with respect to said magnetic disk;
• and
• a processor connected to the magnetic head, to the spindle motor and to the actuator for exchanging signals with the magnetic head, for controlling movement of the magnetic disk and for controlling the position of the magnetic head.

A method of making a magnetic read head comprising the steps of:

• making a spin valve sensor as follows:
• forming a ferromagnetic free layer structure that has a magnetic moment;
• forming a ferromagnetic pinned layer structure that has a magnetic moment;
• forming a nonmagnetic conductive spacer layer between the free layer structure and the pinned layer structure;
• forming an antiferromagnetic metallic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• forming a conductive magnetic keeper layer for providing at least a partial magnetic flux closure for said pinned layer structure;
• and
• forming a nonmagnetic conductive first sense current field producing layer located between the keeper layer and the free layer structure for at least partially counterbalancing sense current fields from layers on an opposite side of the free layer structure.

A method of making a magnetic head assembly comprising the steps of:

• making a write head comprising 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;
• making a read head as follows:
• forming a spin valve sensor;
• connecting first and second hard bias and lead layers to the spin valve sensor;
• forming nonmagnetic nonconductive first and second read gap layers;
• forming the spin valve sensor and the first and second hard bias and lead layers between the first and second read gap layers;
• forming a ferromagnetic first shield layer;
• and
• 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 including:
• forming a ferromagnetic free layer structure that has a magnetic moment;
• forming a ferromagnetic pinned layer structure that has a magnetic moment;
• forming a nonmagnetic conductive spacer layer between the free layer structure and the pinned layer structure;
• forming an antiferromagnetic metallic pinning layer exchange coupled to the pinned layer structure for pinning the magnetic moment of the pinned layer structure;
• forming a conductive magnetic keeper layer for providing at least a partial magnetic flux closure for said pinned layer structure;
• and
• forming a nonmagnetic conductive first sense current field producing layer located between the keeper layer and the free layer structure for at least partially counterbalancing sense current fields from layers on an opposite side of the free layer structure.