In-stack single-domain stabilization of free layers for CIP and CPP spin-valve or tunnel-valve read heads

A MR sensing head comprising:

• a) a first shield proximate a first gap;
• b) a second shield proximate a second gap;
• and
• c) a MR sensor disposed between the first and second gaps wherein the MR sensor includes:
• j) a substrate;
• and
• jj) a thin-film layered structure formed on the substrate, the thin-film layer structure comprising:
• i) a pinned ferromagnetic reference layer;
• ii) a means for pinning a magnetization orientation of the pinned ferromagnetic reference layer along an axis primarily parallel to a direction of an external magnetic field to be sensed, whereby a magnetization direction of the pinned ferromagnetic reference layer remains essentially fixed in the presence of the external magnetic field;
• iii) a ferromagnetic free layer, a magnetization of which being rotated in the presence of the external magnetic field;
• iv) a first nonmagnetic spacer layer disposed between the ferromagnetic free layer and the ferromagnetic reference layer;
• v) a first auxiliary ferromagnetic layer proximate to the ferromagnetic free layer;
• vi) a second nonmagnetic spacer layer disposed between the ferromagnetic free layer and the first auxiliary ferromagnetic layer, the second nonmagnetic spacer layer having physical properties that induce an anti-ferromagnetic coupling between the ferromagnetic free layer and the first auxiliary ferromagnetic layer;
• and
• vii) a pinning layer that directly exchange-couples to the first auxiliary ferromagnetic layer along an axis that is primarily orthogonal to the direction of the magnetization of the ferromagnetic reference;
• wherein the magnetization of the ferromagnetic free layer remains stabilized in a direction primarily orthogonal to that of the ferromagnetic reference layer in an absence of the external magnetic field.

A disk drive comprising:

• a) a magnetic recording disk;
• b) a MR sensing head containing a MR sensor;
• c) an actuator for moving the MR sensing head across the magnetic recording disk;
• d) a motor for spinning the magnetic recording disk relative to the MR sensing head wherein the MR sensor includes:
• j) a substrate;
• and
• jj) a thin-film layered structure formed on the substrate, the thin-film layered structure comprising:
• i) a pinned ferromagnetic reference layer;
• ii) a means for pinning a magnetization orientation of the pinned ferromagnetic reference layer along an axis primarily parallel to a direction of an external magnetic field to be sensed, whereby a magnetization direction of the u ferromagnetic reference layer remains essentially fixed in the presence of the external magnetic field;
• iii) a ferromagnetic free layer, a magnetization of which being rotated in the presence of the external magnetic field;
• iv) a first nonmagnetic spacer layer disposed between the ferromagnetic free layer and the ferromagnetic reference layer;
• v) a first auxiliary ferromagnetic layer proximate to the ferromagnetic free layer;
• vi) a second nonmagnetic spacer layer disposed between the ferromagnetic free layer and the first auxiliary ferromagnetic layer, the second nonmagnetic spacer layer having physical properties that induce an anti-ferromagnetic coupling between the ferromagnetic free layer and the first auxiliary ferromagnetic layer;
• and
• vii) a pinning layer that directly exchange-couples to the first auxiliary ferromagnetic layer along an axis that is primarily orthogonal to the direction of the magnetization of the ferromagnetic reference
• wherein the magnetization of the ferromagnetic free layer remains stabilized in a direction primarily orthogonal to that of the ferromagnetic reference layer in an absence of the external magnetic field.