MAGNETORESISTIVE GRADIOMETER HEAD Russian patent published in 2009 - IPC H01L43/08 

FIELD: electrical engineering.

SUBSTANCE: invention can be used in magnetic field and current sensors, reading heads for reading from magnetic discs and tape, devices for diagnosing printed circuit boards and microcircuit chips, bio-objects (bacteria and viruses), identifying information recorded on magnetic tape and reading information recorded in magnetic ink. The magnetoresistive gradiometer head contains a substrate with a dielectric layer, on which lie four rows of thin-film magnetoresistive strips, connected into a bridge circuit by nonmagnetic low-resistive jumpers and connected in series by the same jumpers in each arm of the bridge circuit. Each thin-film magnetoresistive strip has a bottom and top protective layer, between which there is a ferromagnetic film, first insulating layer on top of the thin-film magnetoresistive strips, on which is formed a control conductor with working parts, lying above the thin-film magnetoresistive strips along each row and connected in form of a meander, a second insulation layer, a planar coil, the working parts of which lie along the axis of easy magnetisation and a protective layer. All four rows of the thin-film magnetoresistive strips lie in one row. The row of thin-film magnetoresistive strips closest to the edge of the nano-element lies at a distance of at least a tenth of the repetition period of the remaining three rows of thin-flim magnetoresistive strips. The control conductor is identically situated in all four rows of the thin-film magnetoresistive strips. A separating high-resistive layer and an additional ferromagnetic film can be put between the ferromagnetic film and the top protective layer in the thin-film magnetoresistive strips.

EFFECT: invention allows for design of a magnetoresistive gradiometer head based on a multilayer metallic nano-structure with planar flow of sensor current, which has a linear volt-oersted characteristic and which allows for measuring local magnetic fields on large areas, without regulating the uniform magnetic field acting on it.

2 cl, 4 dwg