Spin valve sensor having antiparallel (AP) pinned layer structure with low coercivity and high resistance

A magnetic head that has an air bearing surface (ABS) comprising:

• a read head that includes:
• first and second ferromagnetic shield layers:
• first and second nonmagnetic electrically insulative gap layers located between the first and second ferromagnetic shield layers;
• a spin valve sensor responsive to applied magnetic fields;
• the spin valve sensor being located between the first and second gap layers;
• and
• first and second electrically conductive lead layers located between the first and second gap layers and connected to the spin valve sensor for conducting a sense current through the spin valve sensor;
• the spin valve sensor including:
• an antiparallel (AP) pinned layer including first and second ferromagnetic layers and a ruthenium (Ru) layer wherein the ruthenium (Ru) layer is sandwiched between the first and second ferromagnetic layers;
• a pinning layer that has magnetic spins oriented in a first predetermined direction that is perpendicular to the ABS;
• the AP pinned layer being exchange coupled to the pinning layer with the first ferromagnetic layer interfacing the pinning layer so that a magnetic moment of the second ferromagnetic layer is pinned in a second predetermined direction that is antiparallel to said first predetermined direction;
• at least one of the first and second ferromagnetic layers being selected from the group comprising cobalt iron niobium hafnium (CoFeNbHf), cobalt iron niobium (CoFeNb), cobalt iron hafnium (CoFeHf) and cobalt niobium hafnium (CoNbHf);
• a free layer that has a magnetic moment that is free to rotate relative to the second predetermined direction of the AP pinned layer in response to an applied field;
• a nonmagnetic electrically conductive first spacer layer;
• and
• the first spacer layer being located between the free layer and the AP pinned layer.

A magnetic disk drive that includes at least one magnetic head that has an air bearing surface (ABS), the disk drive comprising:

• the magnetic head including a combined read head and write head;
• the read head including:
• first and second ferromagnetic shield layers:
• first and second nonmagnetic electrically insulative gap layers located between the first and second ferromagnetic shield layers;
• a spin valve sensor responsive to applied magnetic fields;
• the spin valve sensor being located between the first and second gap layers;
• and
• first and second electrically conductive lead layers located between the first and second gap layers and connected to the spin valve sensor for conducting a sense current through the spin valve sensor;
• the spin valve sensor including:
• an antiparallel (AP) pinned layer including first and second ferromagnetic layers and a ruthenium (Ru) layer wherein the ruthenium (Ru) layer is sandwiched between the first and second ferromagnetic layers;
• a pinning layer that has magnetic spins oriented in a first predetermined direction that is perpendicular to the ABS;
• the AP pinned layer being exchange coupled to the pinning layer with the first ferromagnetic layer interfacing the pinning layer so that a magnetic moment of the second ferromagnetic layer is pinned in a second predetermined direction that is antiparallel to said first predetermined direction;
• at least one of the first and second ferromagnetic layers being selected from the group comprising cobalt iron niobium hafnium (CoFeNbHf), cobalt iron niobium (CoFeNb), cobalt iron hafnium (CoFeHf) and cobalt niobium hafnium (CoNbHf);
• a free layer that has a magnetic moment that is free to rotate relative to the second predetermined direction of the AP pinned layer in response to an applied field;
• a nonmagnetic electrically conductive first spacer layer;
• the first spacer layer being located between the free layer and the AP pinned layer,
• the write head including:
• first and second pole piece layers and a write gap layer;
• the first and second pole piece layers being separated by the write gap layer at the ABS and connected at a back gap that is recessed rearwardly in the head from the ABS;
• an insulation stack having at least first and second insulation layers;
• at least one coil layer embedded in the insulation stack;
• the insulation stack and the at least one coil layer being located between the first and second pole piece layers;
• and
• the second shield layer and the first pole piece layer being a common layer;
• a housing;
• a magnetic disk rotatably supported in the housing;
• a support mounted in the housing for supporting the magnetic head with its ABS facing the magnetic disk so that the magnetic head is in a transducing relationship with the magnetic disk;
• means for rotating the magnetic disk;
• positioning means connected to the support for moving the magnetic head to multiple positions with respect to said magnetic disk;
• and
• processing means connected to the magnetic head, to the means for rotating the magnetic disk and to the positioning means for exchanging signals with the merged magnetic head, for controlling movement of the magnetic disk and for controlling the position of the magnetic head.

A method of making a combined read and write head that has an air bearing surface (ABS) comprising:

• a making of the read head including:
• forming a ferromagnetic first shield layer;
• forming a nonmagnetic electrically insulative first gap layer on the first shield layer;
• forming a spin valve sensor on the first gap layer as follows:
• forming a pinning layer that has magnetic spins oriented in a first predetermined direction;
• forming an antiparallel (AP) pinned layer as follows:
• forming a first ferromagnetic layer on the pinning layer with a magnetic moment pinned parallel to said first predetermined direction;
• forming a film of ruthenium (Ru) on the first ferromagnetic layer;
• forming a second ferromagnetic layer on the ruthenium (Ru) layer that has a magnetic moment pinned in a second predetermined direction that is antiparallel to said first predetermined direction;
• selecting at least one of the ferromagnetic layers from a group comprising cobalt iron niobium hafnium (CoFeNbHf), cobalt iron niobium (CoFeNb, cobalt iron hafnium (CoNbHf);
• forming a nonmagnetic electrically conductive first spacer layer on the second ferromagnetic layer of the AP pinned layer;
• forming a ferromagnetic free layer on the first spacer layer that has a magnetic moment that is free to rotate relative to the second predetermined direction of the AP pinned layer in response to an applied field;
• forming first and second electrically conductive lead layers on the first gap layer that are connected to the sensor;
• forming a nonmagnetic electrically insulative second gap layer on the sensor, the lead layers and the first gap layer;
• and
• forming a ferromagnetic second shield layer on the second gap layer;
• a making of the write head including:
• forming a write gap layer and an insulation stack with a coil layer embedded therein on the second shield layer so that the second shield layer also functions as a first pole piece for the write head;
• and
• forming a second pole piece layer on the insulation stack and the write gap and connected at a back gap to the first pole piece.