Spin valve sensor with antiparallel magnetization of pinned layers

摘要

A magnetoresistive (MR) sensor comprises a dual differential spin valve structure. Each of the spin valves comprise first (free) and second (pinned) layers of ferromagnetic material separated by a thin film layer of nonmagnetic material. The magnetization direction of the pinned layers of ferromagnetic material in each spin valve is fixed, and their magnetization is set antiparallel to each other. A current flow is produced through the MR sensor, and the variations in voltage across the MR sensor are sensed due to changes in resistance of the MR sensor produced by rotation of the magnetization in the free layers of ferromagnetic material as a function of the magnetic field being sensed.