A SPIN VALVE SENSOR SET BY SENSE CURRENT FIELDS SETTING MAGNETIZATIONS OF PINNED AND FREE LAYERS

摘要

A magnetic bias magnetoresistive (MR) spin valve sensor is provided that does not require an antiferromagnetic layer to set the magnetization direction. A nonmagnetic electrically conductive spacer layer is sandwiched between the ferromagnetic free layer and the pinned layer. The first and second leads are connected to the spin valve sensor and allow current to flow there through. Due to the magnetic coupling between the free layer and the pinned layer, a ferromagnetic coupling field H _FC is induced in the free layer and the pinned layer facing in the first direction and parallel to each other when the sense current flows. When sense current flows, stray field H _DEMAG is induced from the fixed layer to the free layer. Potato field H _DEMAG for the free layer since the first flux guide is magnetically coupled to the first edge of the layers in the ABS and the second flux guide is magnetically coupled to the second edge of the free layer away from the ABS. The influence of is minimized or preferably becomes zero. The sense current flowing through the spin valve sensor causes the sense current field from the fixed layer to equilibrate with the ferromagnetic coupling on the free layer and the sense current field from the free layer adds to the ferromagnetic coupling on the fixed layer. Thus, the magnetic moment of the free layer rotates freely under the influence of the long signal from the rotating magnetic disk and the magnetic moment of the fixed layer is fixed in a predetermined direction perpendicular to the ABS.