Read sensor having an in-stack biasing structure and an AP coupled free layer structure for increased magnetic stability

A magnetic head, comprising:

• first and second shield layers;
• a read sensor formed in between and in electrical contact with the first and the second shield layers;
• the read sensor comprising:
• an antiparallel (AP) coupled free layer structure;
• an in-stack biasing structure which stabilizes the AP coupled free layer structure;
• a nonmagnetic spacer layer between the in-stack biasing structure and the AP coupled free layer structure;
• and
• the AP coupled free layer structure comprising:
• a first AP coupled free layer adjacent the nonmagnetic spacer layer;
• a second AP coupled free layer;
• and
• an antiparallel coupling layer formed between the first and the second AP coupled free layers.

A disk drive, comprising:

• a housing;
• a magnetic disk rotatably supported in the housing;
• a magnetic head;
• a support mounted in the housing for supporting the magnetic head so as to be in a transducing relationship with the magnetic disk;
• a spindle motor for rotating the magnetic disk;
• an actuator connected to the support for moving the magnetic head to multiple positions with respect to said magnetic disk;
• 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;
• the magnetic head, comprising:
• first and second shield layers;
• a read sensor formed in between and in electrical contact with the first and the second shield layers;
• the read sensor comprising:
• an antiparallel (AP) coupled free layer structure;
• an in-stack biasing structure which stabilizes the AP coupled free layer structure;
• a nonmagnetic spacer layer between the in-stack biasing structure and the AP coupled free layer structure;
• and
• the antiparallel (AP) free layer structure, comprising:
• a first AP coupled free layer adjacent the nonmagnetic spacer layer;
• a second AP coupled free layer;
• and
• an antiparallel coupling layer formed between the first and the second AP coupled free layers.