Patent ID: 8514525

Claim:
A magnetoresistive sensor having a stack of layers and capable of sensing external magnetic fields from tracks on a magnetic recording disk when a sense current is applied perpendicular to the planes of the layers in the sensor, the sensor comprising: a carrier having a disk-facing surface and a trailing surface generally orthogonal to said disk-facing surface; a first shield layer formed of magnetically permeable material on said trailing surface, the first shield layer having a cross-track width and an in-plane magnetization direction fixed generally parallel to said disk-facing surface in the presence of the external magnetic field to be sensed; one and only one free ferromagnetic layer having a cross-track width less than one-half the cross-track width of the first shield layer and an in-plane magnetization direction oriented at an angle relative to the magnetization direction of the first shield layer in the absence of an external magnetic field and being substantially free to rotate in the presence of the external magnetic field to be sensed; a nonmagnetic spacer layer between the first shield layer and the free layer; and a ferromagnetic biasing structure for biasing the magnetization direction of the free layer at said angle relative to the magnetization direction of the first shield layer in the absence of an external magnetic field, the biasing structure including a back biasing layer recessed from the disk-facing surface and having a magnetization direction generally orthogonal to the disk-facing surface.