Patent ID: 6396669
Filing Date: 2002-05-28
Classification: B82Y,G11B

Abstract:
A magnetic read head that has an air bearing surface (ABS), comprising:nonmagnetic nonconductive first and second read gap layers; a spin valve sensor located between the first and second read gap layers; ferromagnetic first and second shield layers; the first and second read gap layers being located between the first and second shield layers with the first read gap layer interfacing the first shield layer and the second read gap layer interfacing the second shield layer; the spin valve sensor including: a free layer structure that has a magnetic moment; a ferromagnetic antiparallel (AP) pinned layer structure with a net magnetic moment that produces a net demagnetization field HD through the free layer structure in a direction perpendicular to the ABS; a pinning layer exchange coupled to the AP pinned layer structure for pinning the net magnetic moment of the AP pinned layer structure; and a nonmagnetic conductive spacer layer located between the free layer structure and the AP pinned layer structure; the AP pinned layer structure including: ferromagnetic first and second antiparallel (AP) pinned layers with the first AP pinned layer interfacing the pinning layer and the second AP pinned layer interfacing the spacer layer; an antiparallel (AP) coupling layer located between and interfacing the first and second AP pinned layers; and the second AP pinned layer having a magnetic moment that exerts a ferromagnetic coupling field HFC on the free layer structure in the direction perpendicular to the ABS; a first read gap distance between the first shield layer and a middle of the free layer structure and a second read gap distance between the second shield layer and the middle of the free layer structure wherein one of the first and second read gap distances is greater than the other of the first and second read gap distances; a sense current source for conducting a sense current in a predetermined direction through the sensor for producing a sense current field HI and a net image current field HIM perpendicular to the ABS through the free layer structure with the sense current field HI antiparallel to the net demagnetization field HD, the ferromagnetic coupling field HFC and the net image current field HIM.