A self-biased spin valve sensor with a longitudinally pinned layer

We have developed a novel self-biased spin valve sensor in which a free layer is magnetostatically coupled to a longitudinally and moderately pinned layer. Such spin-valve sensors are more appropriate for GMR/inductive head processes than conventional spin-valve sensors because the direction of pinning is parallel to the desired magnetic anisotropy for the free layer and shields. To fabricate the spin valves, we deposited Ta(3 nm)/NiFe(3 nm)/Cu(2.5 nm)/NiFe(8 nm)/NiMn(15 nm)/Ta(3 nm) films, patterned the spin valve, and attached an Au lead to each of its sides. The transfer curve of this spin valve sensor exhibits excellent linearity without Barkhausen noise. Dynamic range is great in proportion to the sense current, while sensitivity is slightly less than that of conventional spin valve sensors at high sense current levels.